THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 

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V.  5  cop4 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 


PUBLISHED  QUARTERLY 

UNDER  THE  AUSPICES  OF  THE  GRADUATE  SCHOOL 

BY  THE  UNIVERSITY  OF  ILLINOIS 


VOLUME  III 


Urbana,  Illinois 
1916-1917 


Editorial  Committee 


Stephen  Alfred  Forbes       ■  William  Trelease 

Henry  Baldwin  Ward 


TABLE  OF  CONTENTS 

Volume  III 

numi;krs  pages 

1         Studies  on  the  Factors  Controlling  the  Rate  of  Regeneration. 

By  Charles  Zeleiiy  1-170 

(Distributed  Novemlier  29,  1916) 


The   Head-Capsule  and  Mouth-Parts   of   Diptera.     By   Alvah 

Peterson.     With   25   plates 171-284 

(Distributed  December  30,  1016) 


Studies  on  Xorth  .-Xnierican  Polystomidae,  .Aspidogastridae,  and 
Parau'.iihistoniidae.  r>y  Horace  Wesley  Stunkard.  With 
II    plates   285-394 

(Distributed  May  5.   1917) 


4        Color  and  Color-Pattern   Mechanism  of  Tiger  Beetles.     By  Victor 

E.   Slielford.     With   29  black  and  3  colored  plates 395-532 

(Distributed  June  30,  191/) 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 

Vol.111  August,  1916  No,  I 

Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate   School  by 

THE  University  of  Illinois 


Copyright,  igi5 
By  the  University  of  Illinois 
Distributed  November  29,  igi6 


STUDIES  ON  THE   FACTORS 

CONTROLLING  THE  RATE  OF 

REGENERATION 


CHARLES  ZELENY 


Contributions    from    the 
Zoological  Laboratory  of  the  University  of  Illinois,   No.  73 


732172 


TABLE  OF  CONTENTS 


PAGE 

Introduction    7 

The  Rate  of  Regeneration   from  New  Tissue  Compared  with  That   from  Old 

Tissue    9 

The  Effect  of  Successive  Removal  upon  the  Rate  and  Completeness  of  Regen- 
eration    26 

The  Effect  of  Level  of  the  Cut  upon  the  Rate  and  Completeness  of  Regeneration  61 

The  Change  in  Rate  of  Regeneration  during  the  Regenerative  Process 108 

The  Effect  of  Degree  of  Injury  upon  the  Rate  of  Regeneration 136 

The  Completeness  of  Regeneration 158 

Bibliography  167 


RATE    OF    REGENERATION— ZELEXY 


INTRODUCTION. 

The  present  studies  of  the  factors  controlling  rate  of  regeneration 
are  a  continuation  of  previous  work  on  the  subject.  An  advance  in 
knowledge  concerning  certain  of  the  factors  has  made  possible  an  exten- 
sion of  the  experimental  analysis  of  others.  The  present  studies  are 
therefore  closely  related.  In  fact  in  several  cases  a  single  series  of  iudi- 
v-iduals  has  been  of  value  in  connection  with  more  than  a  single  factor. 
The  definite  determinations  of  the  effect  of  level  of  the  cut  and  of  the 
change  in  rate  during  the  regeneration  cycle  have  been  of  particular 
value. 

The  precautions  taken  to  meet  the  demands  of  the  experiments  are 
not  discussed  in  detail  because  they  have  already  been  given  in  previous 
papers.  The  frog  tadpoles  (when  they  can  be  used)  are  in  all  respects 
more  suitable  than  salamander  larvae.  When  collected  late  in  the  fall 
they  can  be  kept  at  a  fairly  constant  size  and  the  results  obtained  under 
these  conditions  are  not  complicated  with  growth  phenomena.  They 
have  proved  to  be  remarkably  uniform  in  several  series.  The  salamander 
larvae  on  the  other  hand  vary  in  rate  of  regeneration  from  day  to  day. 
The  factors  involved  in  this  fluctuation  were  not  discovered  and  could 
not  be  remedied  but  may  be  related  in  some  way  to  the  fact  that  these 
animals  require  living  active  food  and  the  feeding  reactions  are  therefore 
more  complicated  tlian  in  frog  tadpoles  and  more  subject  to  disturbance. 

In  regard  to  certain  factors,  such  as  the  degree  of  injury,  in  which 
expected  differences  in  rate  are  slight  the  writer  has  felt  that  he  might 
be  biased  in  making  the  measurements  and  in  a  number  of  cases  this 
work  was  therefore  delegated  to  a  person  who  had  no  preconceptions 
concerning  the  result. 

In  making  averages  elimination  of  individual  cases  is  avoided 
except  for  a  few  very  aberrant  values.  Such  exceptional  values  are  in 
every  case  however  included  in  the  tables.  In  many  cases  where  only 
slight  differences  are  to  be  expected  several  different  kinds  of  comparisons 
are  made  .so  as  to  bring  out  the  correct  relation  as  completely  as  possible. 

As  in  the  past  all  data  obtained  by  the  writer  on  the  particular 
factors  in  question  are  given.  The  practice  of  selective  elimination  would 
be  dangerous  because  of  the  large  value  of  factors  not  at  present  under 
experimental  control. 


8  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [8 

DiscussioDS  of  the  results  of  other  workers  are  included  in  the  pre- 
vious papers  and  need  not  be  repeated  here.  The  principal  need  at 
present  seems  to  be  an  extension  of  knowledge  of  these  factors  by 
multiplying  the  number  of  series  of  carefully  controlled  experiments. 
"While  it  would  be  interesting  to  know  why  a  particular  series  differs 
from  others  with  respect  to  a  certain  factor  it  is  not  always  possible  to 
discuss  the  matter  profitably  in  the  absence  of  evidence  as  to  all  the 
factors  concerned. 

Particular  emphasis  must  be  laid  on  the  fact  that  in  connection  with 
some  at  least  of  the  factors  it  has  been  possible  to  make  out  very  definite 
quantitative  relations.  These  have  been  checked  up  in  a  number  of  cases 
by  agreement  between  separate  series  of  experiments.  The  success  in  this 
direction  has  made  it  very  probable  that  with  a  more  accurate  control 
of  external  conditions  there  will  be  a  considerable  further  advance  in 
our  knowledge  of  the  factors  controlling  rate  of  regeneration. 


RATE    OF    REGEXERATION—ZELESY 


PART  I 

THE  RATE  OF  REGENERATION  FROM  NEW  TISSUE  COM- 
PARED WITH  THAT  FROM  OLD  TISSUE 

In  comparing  first  and  second  regenerations  from  the  same  level 
one  of  the  diflSculties  that  presents  itself  is  tlie  impossibility  of  making 
the  second  cut  exactly  in  the  path  of  the  first.  This  is  true  not  only 
because  of  the  error  in  manipulation  but  also  because  the  old  and  the 
new  tissues  become  intermingled  and  do  not  retain  a  distiuct  dividing 
line.  At  the  cut  surface  there  is  old  tissue  alone,  old  and  new  tissue, 
or  new  tissue  alone  according  as  the  second  cut  comes  inside  of  the  first 
level,  exactly  at  the  level,  or  outside  of  it. 

The  experiments  about  to  be  described  were  devised  with  a  view  to 
the  testing  of  the  relative  rates  from  old  and  from  new  tissue.  Other 
factors  being  eliminated,  are  new  cells  which  are  recently  produced  in 
a  regenerating  part  able  to  carry  on  a  repetition  of  the  process  more 
expeditiously  than  old  cells  which  have  not  been  directl}^  concerned  in 
such  a  process? 

There  has  been  no  selective  elimination  of  data.  As  in  former 
papers  of  a  similar  character  all  the  data  obtained  by  the  author  on  the 
topic  at  hand  are  included. 

Experiment  I       Series  3628-3675 

Tadpoles  of  Rana  clamitans  with  an  average  length  of  33.4 
mm.  were  used.  They  were  fed  just  enough  to  keep  them  in  good 
condition  without  much  growth.  AH  were  collected  at  one  time  in  a 
single  pool  and  during  the  course  of  the  experi^ient  factors  apart  from 
the  one  under  investigation  were  made  as  nearly  alike  as  possible.  This 
elimination  of  outside  factors  was  facilitated  by  subdividing  the  tad- 
poles into  sets  of  two  each,  the  two  indiNnduals  of  a  set  being  exactly 
alike  except  for  the  factor  under  consideration  and  one  being  used  for 
regeneration  from  old  tissue  and  the  other  for  regeneration  from  new 
tissue. 


10 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[10 


Within  each  set  the  tail  of  tadpole  1  was  removed  at  B  (Fig.  1) 
and  the  tail  of  tadpole  2  at  A.  The  distance  between  A  and  B  was  2 
or  3  mm.  After  21  days  of  regeneration  the  second  operation  on 
both  tadpoles  came  between  A  and  B  and  tlierefore  in  old  tissue  in 
tadpole  1  and  in  new  tissue  in  tadpole  2.     This  procedure,  insuring 


^       B 


Figure  1.  Outline  of  tadpole  of  Rana  claiiiitans-  Individuals  used  for  re- 
generation from  old  tissue  have  the  original  removal  level  at  B  and  the  second 
level  at  A.  Individuals  used  for  regeneration  from  nevif  tissue  have  the  original 
removal  level  at  A  and  the  second  level  at  B.  Regenerations  from  the  second 
levels  are  compared. 

approximately  the  same  level  in  the  two  cases,  is  necessary  because  level 
of  the  cut  has  a  great  influence  upon  rate  of  regeneration.  Eleven  pairs 
of  individuals  were  used  in  the  comparison.  The  precautions  taken  to 
eliminate  possible  error  are  treated  fully  elsewhere  for  similar  cases 
(Zeleny  1909a,  1909b). 

The  data  are  given  in  Table  1.  The  removed  tail  lengths  are  the 
lengths  of  the  original  removed  portions  of  the  tail  plus  or  minus  the 


EXPLANATION  OP  TABLE  I. 

Note  1.  The  removed  length  is  the  length  of  the  original  removed  portion 
of  the  tail  plus  or  minus  the  distance  of  the  new  cut  surface  from  the  dividing 
line  between  the  old  and  new  tissue. 

Note  2.  The  lengths  as  given  are  the  living  lengths.  Measurements  were 
made  on  material  killed  in  Gilson's  mercuro-nitric  mixture  and  preserved  in 
85%  alcohol.  Sets  I  and  IX  were  measured  both  when  alive  and  after  killing 
and  preserving.  From  tkem  the  shrinkage  coefBcient  was  obtained  and  this 
made  possible  the  reduction  of  all  the  data  to  the  living  basis. 

Note  3.  The  specific  amount  regenerated  in  any  case  is  the  amount  regen- 
erated per  unit  of  removed  length. 

Note  4.  The  average  includes  only  the  sets  in  which  both  individuals  are 
present. 


11] 


RATE    OF    REGEXERATION—ZELEXy 


TABLE  I. 
Series  3628-3675 


Old  or  Nev 
tissue 
at  out 
surface 


Old 
new 


old 

II 

new 

old 

III 

new 

old 

IV 

new 

old 

V 

new 

old 

VI 

new 

old 

VII 

new 

old 

VIII 

new 

old 

IX 

new 

old 

X 

new 

old 

XI 

new 

Averag 

e  of 

old 

Averag 

e  of 

new 

Old— a 

dead 

New — i 

ihea 

i 

Cata- 
log 
Dumber 


Total 
length 
mm. 


moved 
length 
mm. 


Old — Times  ahead 
New — Times  ahead 


3628 
3629 


3633 
3632 


3636 
3637 


3641 
3640 


3645 
3644 


3649 
3648 


3652 
3653 


3656 
3657 


3660 
3661 


3668 
3669 


3672 
3673 


38.0 

24.1 

39.2 

24.6 

35.7 

23.2 

33.8 

22.1 

35.8 

23.1 

38.4 
32.9 

25.0 

20.8 

31.4 

20.4 

37.5 

23.8 

42.8 

29.2 

37.0 

25.6 

35.9 

23.3 

31.3 

20.8 

29.0 

19.2 

31.8 

21.1 

33.0 

22.0 

26.5 

17.0 

29.4 

19.0 

31.1 

20.8 

32.4 

21.8 

24.4 

15.8 

28.5 

18.1 

32.9 

21.5 

34.0 

22.2 

13.2 
12.8 


12.3 
10.2 


12.8 
11.9 


11.3 
9.3 


11.5 
15.1 


11.2 
9.9 


13.2 
11.7 


9.6 
8.7 


9.2 
8.9 


8.6 
8.7 


11.3 
10.7 


Regen-  I  Specific 
erated      length 
length      regen- 

mm.      I  erated 

2.2 

2.3 


Regen-  I  Specific 

erated  I    length 

length  I    regen- 

mm  I  erated 


2.0 
1.8 


2.0 
2.4 


1.7 
2.2 


2.2 
2.3 


2.3 
2.1 


2.4 

2.7 


2.5 
2.0 


1.6 
1.8 


2.7 
1.9 


2.16 
2.15 


0.17 
0.18 


O.IG 
0.18 


0.16 
0.20 


0.15 
0.24 


0.19 
0.15 

0.21 
0.21 


3.5 
3.1 


3.25 
3.5 


3.1 
3.1 


0.27 
0.24 


0.25 
0.29 


0.28 
0.31 


0.26 


0.18 
0.23 


0.26 
0.23 


0.17 
0.20 


0.31 
0.22 


0.196 
0.204 


31/2 

6/2 


3.6 


3.5 
3.0 

2.3 
2.5 

3.5 
3.5 


0.07 


0.36 
0.34 

0.25 
0.28 

0.41 
0.40 

0.303 
0.310 


12  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [12 

distances  of  the  new  cut  surface  from  the  dividing  line  between  the  old 
and  the  new  tissue.  The  regenerated  lengths  as  given  are  the  living 
lengths.  Measm-ements  were  made  on  material  killed  in  Gilson's  mer- 
curo-nitrie  fluid  and  preserved  in  85%  alcohol.  Sets  I  and  IX  were 
measured  both  wlien  alive  and  after  killing  and  preserving.  From  them 
the  shrinkage  coefficient  was  obtained  and  this  made  possible  the  reduc- 
tion of  all  tlie  data  to  the  living  basis.  The  averages  include  only  the 
sets  in  which  both  individuals  are  present.  The  specific  amount  of 
regeneration  is  the  amount  regenerated  per  unit  of  removed  length.  It 
has  been  shown  that  within  wide  limits  this  is  a  constant  if  the  only- 
variable  in  the  experiment  is  the  amount  removed.  This  statement  holds 
for  all  levels  in  the  present  experiment. 

The  table  shows  that  the  average  amount  regenerated  at  the  end 
of  six  days  is  2.16  mm.  from  the  old  tissue  levels  and  2.15  mm. 
from  the  new  tissue  levels.  The  new  tissue  levels  however  rep- 
resent the  shorter  amount  removed,  10.7  mm.  as  opposed  to  11.3 
for  the  old  tissue  levels.  This  gives  an  average  specific  rate  of  0.204 
for  the  new  levels  and  0.196  for  the  old  levels.  The  difference  is  proba- 
bly not  significant.  The  individual  specific  amoimts  in  pairs,  putting 
the  old  tissue  first  and  the  new  tissue  second  in  each  case,  are  0.17  and 
0.18,  0.16  and  0.18.  0.16  and  0.20,  0.15  and  0.24,  0.19  and  0.15,  0.21 
and  0.21,  0.18  and  0.23,  0.26  and  0.23,  0.17  and  0.20,  and  0.31  and  0.22. 
The  old  tissue  is  ahead  three  times,  the  new  six  times  and  there  is  a  tie 
in  one  case. 

At  the  end  of  eight  days  the  result  is  similar.  There  is  a  slight 
advantage  in  favor  of  the  new  tissue  level  but  this  cannot  be  considered 
as  significant.  The  average  amount  regenerated  is  3.19  mm.  from  old 
tissue  levels  and  3.12  mm.  from  new  tissue  levels.  The  specifile 
amount  regenerated  is  0.303  for  the  old  and  0.310  for  the  new  level. 
The  individual  amounts  by  pairs  putting  the  old  tissue  level  first  as 
before  are  0.27  and  0.24,  0.25  and  0.29,  0.28  and  0.31,  0.36  and  0.34, 
0.25  and  0.28,  and  0.41  and  0.40.  Each  level  is  ahead  of  the  other  in 
three  of  the  six  cases. 

Experiment  II      Series  3676-3765 

Tadpoles  of  Rana  clamitans  with  an  average  length  of  forty 
mm.  were  used.  The  experiment  was  designed  for  a  study  of  the 
effect  of  successive  removal  on  the  rate  of  regeneration  but  incidentally 
furnishes  valuable  data  for  the  present  problem.  In  removing  the  re- 
generated portion,  the  cut  in  most  cases  did  not  come  exactly  at  the 
border.  In  some  cases  it  was  too  near  the  base  of  the  tail  and  therefore 
the  cells  at  the  cut  surface  were  old  unregenerated  cells.    In  other  cases 


13]  RATE    OF    REGEXERATIOX—ZELENY  13 

it  was  too  near  the  tip  of  the  tail  and  the  cells  at  the  cut  surface  were 
newly  regenerated  ones. 

The  operations  were  at  different  levels  in  dift'erent  individuals  but 
the  determination  of  the  specific  amounts  of  regeneration  accoi'ding  to 
the  method  given  in  the  explanation  of  Experiment  I  eliminates  these 
differences  within  wide  limits.  It  does  not  hold  when  the  level  of  the 
cut  is  very  near  the  tip  or  near  the  base  of  the  tail.  In  the  present 
experiment  the  specific  amount  is  a  fair  constant  for  all  removed 
lengths  of  over  4  mm.  The  individuals  with  a  removed  length  of 
less  than  4  mm.  are  therefore  treated  separately.  Likewise  it  does 
not  hold  for  the  first  few  days  of  regeneration  during  which  regenera- 
tion is  confined  to  active  migration  of  cells  over  the  cut  surface  without 
any  new  formation  by  cell  division.  Separate  comparisons  are  made  at 
4,  6,  8,  10,  121/4,  18  and  56  days  of  regeneration.  The  data  are  given 
in  Tables  2  to  17. 

Taking  first  the  cases  with  a  removed  length  of  over  4  mm.  there 
is  at  four  days  a  specific  amount  of  0.043  for  old  tissue  and  of 
0.045  for  new  tissue.  At  six  days  the  amounts  are  respectively  0.135 
and  0.143,  at  eight  days  0.216  aiid  0.224,  at  ten  days  0.292  and  0.293, 
at  twelve  and  a  half  days  0.331  and  0.337,  at  eighteen  days  0.352  and 
0.348,  and  at  fifty-six  days  0.345  and  0.346.  The  two  are  approximately 
equal  though  in  six  out  of  the  seven  cases  the  new  tissue  is  ahead.  The 
average  difference  in  favor  of  the  new  tissue  is  0.003. 

For  removed  amounts  of  less  than  4  mm.  the  data  are  un- 
satisfactory because  there  are  only  three  individuals  with  regeneration 
from  new  tissues.  The  data  are  however  of  value  in  comparison  with 
the  others.  The  specific  amounts  at  the  different  days,  again  putting 
the  old  tissue  first  in  each  case,  are  0.119  and  0.160  for  four  days,  0.317 
and  0.327  for  six  days,  0.444  and  0.467  for  eight  days,  0.506  and  0.520 
for  ten  daj'S,  0.517  and  0.517  for  twelve  and  a  half  days,  0.501  and  0.507 
for  eighteen  days,  and  0.475  and  0.325  for  fifty-six  days.  In  the  last 
the  absorption  of  the  tail  had  begun  before  the  measurement  was  made 
and  the  comparison  is  therefore  not  valid  for  our  purposes.  In  the 
first,  0.119  for  old  and  0.160  for  new  at  four  daj'S,  the  great  difference 
between  individual  cases  on  eacli  side  makes  a  comparison  of  doubtful 
validity.  There  are  other  data  however  which  make  it  probable  that  tlio 
initial  migration  of  the  cells  takes  place  more  rapidly  from  new  tlum 
from  old  tissue.  For  the  other  levels  there  is  on  the  average  a  slight 
difference  (0.011)  in  favor  of  the  regeneration  from  new  tissue.  With  but 
a  single  exception,  which  is  a  tie,  the  new  tissue  is  ahead  of  the  old. 
The  differences  favoring  the  new  tissue  are  greater  than  those  for  the 
larger  removals.    This  again  may  be  due  to  the  fact  that  a  larger  percent- 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[14 


age  of  the  regenerated  material  is  derived  from  the  old  by  migration  and 
a  smaller  percentage  by  cell  division.  The  data  unfortunately  are  based 
on  such  a  small  number  of  individuals,  especially  in  the  case  of  new  tissue 
levels,  that  too  much  stress  should  not  be  laid  on  the  differences. 


TABLE  2 
Series  3676-3765       Over  4  millimeters  removed      Regeneration;  4  days 


Note  1.  No.  3734  is  left  out  in  making  up  the  averages  because  its  specific 
amount  from  six  days  of  regeneration  on  is  very  much  in  excess  of  that  of 
any  of  the  others.  A  probable  explanation  is  that  the  end  of  the  tail  in  this  indi- 
vidual had  been  removed  and  regeneration  had  just  started  when  the  present 
operations  were  begun.  If  this  is  true  it  belongs  to  a  longer  removed  length 
than  indicated  and  the  specific  rate  is  wrong.  Besides  a  highly  exceptional 
Individual  even  if  not  explained  should  be  left  out  in  determining  the  average 
value. 


15] 


RATE    OF    REGEXERATION—ZELENY 


Series  3676-3765 


TABLE  3 
Over  4  millimeters  removed       Regeneration:   6  days 


Series  3676-3765 


TABLE  4 
Over  4  millimeters  removed 


Oldt 

ssue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 
mm. 

Specific 
length 
regen- 
erated 

3720 

4.7 

0.84 

0.18 

3756 

4.8 

1.0 

0.21 

3648 

5.5 

0.7 

0.13 

3751 

6.7 

1.1 

0.16 

3715 

7.9 

0.9 

0.11 

3697 

7.3 

1.2 

0.16 

3757 

8.0 

1.2 

0.15 

3721 

8.5 

1.3 

0.15 

3694 

8.7 

1.5 

0.17 

3733 

8.5 

1.0 

0.12 

3685 

9.3 

1.2 

0.13 

3734 

8.5 

2.1 

0.25 

3686 

14.5 

2.1 

0.14 

3739 

9.4 

1.0 

0.11 

3753 

16.8 

2.0 

0.12 

3722 

12.5 

1.6 

0.13 

3723 

18.4 

2.3 

0.12 

3716 

12.7 

1.7 

0.13 

3699 

21.0 

2.2 

0.10 

3698 

12.9 

1.5 

0.12 

3759 

15.5 

2.0 

0.13 

3705 

17.6 

2.0 

0.11 

3717 

17.6 

2.6 

0.15 

3687 

19.7 

2.6 

0.18 

Average 

0.135 

Average 

1 

0.143 

Regeneration:  8  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 

removed 

mm. 

Length 
regen- 
erated 
mm. 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3720 

4.7 

1.1 

0.23 

3756 

4.8 

1.3 

0.27 

3684 

.    5.5 

1.2 

0.22 

3751 

6.7 

1.7 

0.25 

3715 

7.9 

1.7 

0.22 

3697 

7.3 

1.7 

0.23 

3757 

8.0 

2.1 

0.26 

3721 

8.5 

1.9 

0.22 

3694 

8.7 

2.2 

0.25 

3733 

8.5 

1.9 

0.22 

3685 

9.3 

1.9 

0.20 

3734 

8.5 

3.1 

0.36 

3686 

14.5 

3.4 

0.23 

3739 

9.4 

1.8 

0.19 

3753 

16.8 

2.5 

0.15 

3722 

12.5 

2.6 

0.21 

3723 

18.4 

3.7 

0.20 

3716 

12.7 

2.4 

0.19 

3699 

21.0 

4.3 

0.20 

3698 

12.9 

3.3 

0.26 

3759 

15.5 

3.0 

0.19 

3705 

17.6 

3.6 

0.20 

3717 

17.6 

3.6 

0.20 

3687 

19.7 

5.6 

0.28 

Average 

0.216 

Average 

0.224 

ILLLXOIS    BIOLOGICAL    MONOGRAPHS 


TABLE  5 
Series  3676-3765       Over  4  millimeters  removed       Regeneration:  10  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3720 

4.7 

1.3 

0.28 

3756 

4.8 

1.7 

0.35 

3684 

5.5 

1.4 

0.25 

3751 

6.7 

2.1 

0.31 

3715 

7.9 

2.3 

0.29 

3697 

7.3 

2.2 

0.30 

3757 

8.0 

2.8 

0.35 

3721 

8.5 

2.3 

0.27 

3694 

8.7 

3.2 

0.37 

3733 

8.5 

2.4 

0.28 

3685 

9.3 

2.3 

0.25 

3734 

8.5 

4.5 

0.53 

3686 

14.5 

4.8 

0.33 

3739 

9.4 

2.4 

0.26 

3753 

16.8 

3.8 

0.23 

3722 

12.5 

3.6 

0.29 

3723 

18.4 

5.3 

0.29 

3716 

12.7 

3.4 

0.27 

3699 

21.0 

5.9 

0.28 

3698 

12.9 

4.3 

0.33 

3759 

15.5 

4.2 

0.27 

3705 

17.6 

4.8 

0.28 

3717 

17.6 

5.2 

0.30 

3687 

19.7 

6.0 

0.30 

Average 

0.292 

Average 

0.293 

Series  3676-3765 


TABLE  6 
Over  4  millimeters  removed 


Regeneration;   12-13  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3720 

4.7 

1.3 

0.28 

3756 

4.8 

1.8 

0.37 

3684 

5.5 

1.4 

0.25 

3751 

6.7 

2.4 

0.36 

3715 

7.9 

2.6 

0.33 

3697 

7.3 

2.4 

0.33 

3757 

8.0 

3.1 

0.39 

3721 

8.5 

2.6 

0.31 

3694 

8.7 

3.4 

0.39 

3733 

8.5 

2.6 

0.31 

3685 

9.3 

2.8 

0.30 

3734 

8.5 

5.7 

0.67 

3G86 

14.5 

5.3 

0.37 

3739 

9.4 

3.0 

0.32 

3753 

16.8 

5.2 

0.31 

3722 

12.5 

3.9 

0.31 

3723 

18.4 

6.5 

0.35 

3716 

12.7 

4.2 

0.33 

3699 

21.0 

7.1 

0.34 

3698 

12.9 

5.0 

0.39 

3759 

15.5 

4.8 

0.31 

3705 

17.6 

6.4 

0.36 

3717 

17.6 

6.0 

0.34 

3687 

19.7 

6.6 

0.34 

Average 

0.331 

Average 

0.337 

RATE    OF    REGENERATION  —  ZELENY 


Series  3676-3765 


TABLE  7 
Over  4  millimeters  removed 


Regeneration:    17-18-19  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 

removed 

mm. 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 
mm. 

Specific 
length 
regen- 
erated 

3720 

4.7 

1.3 

0.28 

3756 

4.8 

1.6 

0.33 

3684 

5.5 

1.5 

0.27 

3751 

6.7 

2.5 

0.37 

3715 

7.9 

2.6 

0.33 

3697 

7.3 

2.3 

0.32 

3757 

8.0 

3.2 

0.40 

3721 

8.5 

2.3 

0.27 

3694 

8.7 

3.4 

0.39 

3733 

8.5 

2.6 

0.31 

3685 

9.3 

3.0 

0.32 

3734 

8.5 

6.4 

0.75 

3686 

14.5 

5.2 

0.36 

3739 

9.4 

2.9 

0.31 

3753 

16.8 

6.4 

0.38 

3722 

12.5 

3.5 

0.28 

3723 

18.4 

8.1 

0.43 

3716 

12.7 

5.1 

0.40 

3699 

21.0 

7.5 

0.36 

3698 

12.9 

5.4 

0.42 

3759 

15.5 

6.7 

0.43 

3705 

17.6 

6.2 

0.35 

3717 

17.6 

6.7 

0.38 

3687 

19.7 

7.0 

0.36 

Average 

0.352 

Average 

0.348 

TABLE  8 
Series  3676-3765       Over  4  millimeters  removed 


Regeneration:    55-56-57  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 

removed 

mm. 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3720 

4.7 

1.3 

0.28 

3756 

4.8 

— 

3684 

5.5 

1.4 

0.25 

3751 

6.7 

2.3 

0.34 

3715 

7.9 

2.8 

0.35 

3697 

7.3 

2.1 

0.29 

3757 

8.0 

3.1 

0.39 

3721 

8.5 

2.2 

0.26 

3694 

8.7 

— 

3733 

8.5 

2.8 

0.33 

3685 

9.3 

2.6 

0.28 

3734 

8.5 

6.6 

0.78 

3686 

14.5 

— 

3739 

9.4 

— 

3753 

16.8 

7.1 

0.42 

3722 

12.5 

4.2 

0.34 

3723 

18.4 

8.3 

0.45 

3716 

12.7 

4.4 

0.35 

3699 

21.0 

7.2 

0.34 

3698 

12.9 

5.4 

0.42 

3759 

15.5 

6.6 

0.43 

3705 

17.6 

6.0 

0.34 

3717 

17.6 

6.4 

0.36 

3687 

19.7 

— 

Average 

0.345 

Average 

0.346 

ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[18 


Series  3676-3765 


TABLE  9 
Over  4   millimeters   removed 


Summary   Tables  2  to  8 


Table 
number 

Days  of 
regeneration 

Old   tissue 

Specific 

length    of 

regeneration 

New  tissue 

Specific 

lengtli    of 

regeneration 

Old 
ahead 

New 
ahead 

2 

4 

0.043 

0.045 

0.002 

3 

6 

0.135 

0.143 

0.008 

4 

8 

0.216 

0.224 

0.008 

5 

10 

0.292 

0.293 

0.001 

6 

12,13 

0.331 

0.337 

0.006 

7 

17,18,19 

0.352 

0.348 

0.004 

8 

55,  56,  57 

0.345 

0.346 

0.001 

Average 

0.003 

TABLE  10 
Series  3676-3765      Less  than  4  millimeters  removed       Regeneration:  4  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.27 

0.27 

3696 

2.1 

0-48 

0.23 

36S2 

1.6 

0.18 

0.11 

3749 

2.8 

0.30 

0.11 

3730 

1.6 

0.39 

0.24 

3750 

3.5 

0.48 

0.14 

3754 

1.6 

0.06 

0.04 

3718 

2.1 

0.06 

0.03 

3731 

2.7 

0.15 

0.06 

3713 

2.8 

0.36 

0.13 

3719 

3.1 

0.36 

0.12 

3701 

3.2 

0.42 

0.13 

Average 

0.119 

Average 

0.160 

19] 


RATE    OF    REGE.XERATIOX—ZELEXV 


TABLE  11 
Series  3676-3765      Less  than  4  millimeters  removed       Regeneration:  6  days 


Old  tissue 

New 

tissue 

Catalog 
number 

Length 

removed 

mm. 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.6 

0.46 

3696 

2.1 

0.85 

0.40 

3682 

1.6 

0.6 

0.37 

3749 

2.8 

0.6 

0.21 

3730 

1.6 

0.75 

0.47 

3750 

3.5 

1.3 

0.37 

3754 

1.6 

0.55 

0.34 

3718 

2.1 

0.45 

0.21 

3731 

2.7 

0.5 

0.19 

3713 

2.8 

0.8 

0.29 

3719 

3.1 

0.84 

0.27 

3701 

3.2 

0.8 

0.25 

Average 

0.317 

Average 

0.327 

Series  3676-3765 


TABLE  12 
Less  than  4  millimeters  removed 


Regeneration:  8  days 


Old  tissue 

New 

tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

0.69 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 
mm. 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.9 

3696 

2.1 

1.0 

0.48 

3682 

1.6 

0.9 

0.56 

3749 

2.8 

1.2 

0.43 

3730 

1.6 

0.9 

0.56 

3750 

3.5 

L7 

0.49 

3754 

1.6 

0.9 

0.56 

3718 

2.1 

0.7 

0.33 

3731 

2.7 

0.8 

0.29 

3713 

2.8 

0.9 

0.32 

3719 

3.1 

1.1 

0.35 

3701 

3.2 

1.1 

0.34 
0.444 

Average 

Average 

0.467 

20 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[20 


Series  3676-3765 


TABLE  13 
Less  than  4  millimeters  removed 


Regeneration:    10  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.9 

0.69 

3696 

2.1 

1.1 

0.52 

3682 

1.6 

1.0 

0.62 

3749 

2.8 

1.4 

0.50 

3730 

1.6 

0.9 

0.56 

3750 

3.5 

1.9 

0.54 

3754 

1.6 

1.1 

0.69 

3718 

2.1 

1.0 

0.48 

3731 

2.7 

1.0 

0.37 

3713 

2.8 

0.9 

0.32 

3719 

3.1 

1.4 

0.45 

3701 

3.2 

1.2 

0.37 

Average 

0.506 

Average 

0.520 

Series  3676-3765 


TABLE   14 
Less  than  4  millimeters  removed 


Regeneration:  12-13  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.9 

0.69 

3696 

2.1 

1.0 

0.48 

3682 

1.6 

1.0 

0.62 

3749 

2.8      ;         1.4 

0.50 

3730 

1.6 

0.9 

0.56 

3750 

3.5 

2.0 

0.57 

3754 

1.6 

1.2 

0.75 

3718 

2.1 

1.0 

0.48 

3731 

2.7 

1.0 

0.37 

3713 

2.8 

0.9 

0.32 

3719 

3.1 

1.4 

0.45 

3701 

3.2 

1.3 

0.41 

Average 

0.517 

Average 

0.517 

RATE    OF    RECEKERATIOX  —  ZELESY 


TABLE  15 
Series  3676-3765     Less  than  4  millimeters  removed     Regeneration:  17-18-19  days 


Old  tissue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.9 

0.69 

3696 

2.1 

1.0 

0.48 

3682 

1.6 

1.0 

0.62 

3749 

2.8 

1.3 

0.47 

3730 

1.6 

0.9 

0.56 

3750 

3.5 

2.0 

0.57 

3754 

1.6 

1.2 

0.75 

3718 

2.1 

0.5 

0.24 

3731 

2.7 

— 

3713 

2.8 

0.9 

0.32 

3719 

3.1 

1.3 

0.42 

3701 

3.2 

1.3 

0.41 

Average 

0.501 

Average 

0.507 

TABLE  16 
Series  3676-3765     Less  than  4  millimeters  removed     Regeneration:  55-56-57  days 


Oldti 

ssue 

New  tissue 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

0.54 

Catalog 
number 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

3676 

1.3 

0.7 

3696 

2.1 

0.7 

0.33 

3682 

1.6 

1.1 

0.69 

3749 

2.8 

0.9 

0.32 

3730 

1.6 

0.7 

0.44 

3750 

3.5 

— 

3754 

1.6 

1.1 

0.69 

3718 

2.1 

— 

3731 

2.7 

— 

3713 

2.8 

0.5 

0.18 

3719 

3.1 

— 

3701 

3.2 

1.0 

0.31 

Average 

0.475 

Average 

0.325 

22 


ILLIXOIS    BIOLOGICAL    MONOGRAPhlS 


TABLE    17 
Series  3676-3765       Less  than  4  millimeters  removed       Summary  Tables  10  to  16 


Table 
number 

Days  of 
regeneration 

Old   tissue 

Specific 

length    of 

regeneration 

New   tissue 

Specific 

length    of 

regeneration 

Old 
ahead 

New 
ahead 

10 

4 

0.119 

0.160 

0.041 

11 

6 

0.317 

0.327 

0.010 

12 

8 

0.444 

0.467 

0.023 

13 

10 

0.506 

0.520 

0.014 

14 

12,13 

0.517 

0.517 

0.000 

0.000 

15 

17,18,  19 

0.501 

0.507 

0.006 

16 

55,  56,  57 

0.475 

0.325 

0.150 

Average 

■ 

0.011 

Note  1.  Because  of  the  great  variability  in  the  data  the  average  for  the 
four-day  period  is  not  of  much  value  and  is  therefore  not  included  In  the  grand 
average. 

Note  2.  The  absorption  of  the  regenerated  portion  of  the  tail  was  pro- 
ceeding so  rapidly  by  the  fifty-fifth  day  of  regeneration  that  this  average 
should  not  be  included  in  the  grand  average. 


Experiment  III       Series  3557-3624 

This  experiment  was  planned  for  a  study  of  the  effect  of  repeated 
removal  and  regeneration  upon  the  rate  of  metamorphosis  but  it  yields 
data  of  value  for  the  present  problem.  Tadpoles  of  Rana  clamiians 
with  an  average  length  of  about  40  mm.  were  used.  In  some  cases 
the  cuts  were  made  inside  of  the  first  level  and  therefore  in  old 
tissue  and  in  other  cases  outside  of  tlie  first  level  and  therefore  in  new 
tissue. 

The  data  include  third,  fourth  and  fifth  successive  regenerations. 
The  time  of  regeneration  is  37  days  for  the  third  and  36  days  for  the 
fourth  and  for  the  fifth  regenerations.  The  length  of  time  is  more  than 
sufficient  for  the  completion  of  the  process  of  regeneration  in  so  far  as 
it  is  completed.  The  data  therefore  do  not  serve  for  the  rate  but  for 
the  completeness  of  regeneration  from  old  as  compared  with  new  levels. 
Approximately  one-half  of  the  original  tail  length  was  removed  but 
measurements  were  not  made  of  individual  removed  lengths,  so  that 


23] 


RATE    OF    REGEXERATIOX—ZELENY 


23 


specific  rates  of  regeneratiou  can  not  be  calculated.  However  the  re- 
moved lengths  were  so  nearly  alike  as  to  make  the  regenerated  lengths 
of  value  in  direct  comparison. 

The  data  are  given  in  Table  IS.  The  average  length  of  the 
third  regeneration  is  7.9  mm.  for  both  the  old  and  the  new  tissue 
basis.  For  the  fourth  regeneration  the  value  from  old  tissue  is 
5.3  mm.  and  from  new  tissue  5.5  mm.  The  corresponding  values 
for  the  fifth  regeneration  are  6.6  mm.  and  5.9  mm.  Averaging 
the  individual  eases  for  all  three  regenerations  the  old  tissue  average 
is  6.5  mm.  and  the  new  tissue  average  6.6  mm.,  an  advantage  in 
favor  of  the  latter  of  0.1  mm.  This  difference  can  not  be  consid- 
ered as  significant,  especiall.y  since  for  the  individual  regenerations 
the  two  levels  give  equal  regenerated  lengths  for  the  third,  the  new  is 
slightly  ahead  at  the  fourth  and  the  old  is  ahead  at  the  fifth. 

On  the  whole  the  data  for  Experiment  III  agree  witli  those  for 
Experiments  I  and  II.  There  is  no  striking  difference  between  com- 
pleteness of  regeneration  from  old  and  from  new  tissue  levels,  though 
a  small  difference  favoring  the  latter  persists  in  practically  all  the 
comparisons. 

TABLE  18 

Rana   clamitans  Series    3557-3624 

Regenerated  tail  length  from  new  tissue  compared  with  that  from  old  tissue 

during  the  third,  fourth  and  fifth  regenerations 


Third 
regeneration 

37   Days 

Fourth 
regeneration 

Fifth 
regeneration 

Third,  fourth  and 

fifth 

regenerations 

combined 

36 

Days 

36  Days 

Old 

New 

Old 

New 

Old 

New- 

Old 

New 

tissue 

tissue 

tissue 

tissue 

tissue 

tissue 

tissue 

tissue 

2.0 

5.7 

4.4 

4.9 

4.7 

5.2 

6.8 

6.6 

4.5 

.5.4 

5.5 

5.7 

6.9 

8.0 

4.8 

5.5 

6.2 

5.9 

7.5 

8.3 

4.9 

6.1 

6.5 

6.8 

7.9 

9.3 

5.0 

7.1 

9.0 

9.7 

."..1 

7.2 

9.4 

5.S 

t;.i 

7.3 

7.9 
8.0 

Average 

in  mm. 

7.9 

7.9 

5.3 

5.5 

6.6 

5.9 

6.5 

6.6 

Difference 

in  mm. 

0.0 

0.0 

+0.2 

4-0.7 

-fO.1 

24  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [24 

Discussion 

While  tlie  knowledge  of  the  relative  rates  of  regeneration  for  old 
and  new  tissue  is  essential  for  accurate  determination  of  other  factors 
its  main  interest  is  in  its  bearing  on  the  question  of  the  character  of 
control  of  the  process  of  regeneration.  Evidence  from  a  great  many 
directions  points  toward  the  conclusion  that  regeneration  is  not  wholly 
a  direct  response  of  the  injured  cells  at  the  cut  surface  nor  of  those  in 
the  immediate  neighborhood  of  the  cut  surface.  It  is  more  and  more 
evident  that  conditions  in  parts  of  the  body  remote  from  the  injured 
region  are  involved.  If  rate  of  regeneration  were  determined  wholly 
by  the  character  of  the  cells  at  the  cut  surface  we  would  expect  that 
cells  in  process  of  active  proliferation,  such  as  those  that  are  starting 
to  build  up  a  new  tail,  would  respond  much  more  promptly  than  those 
which  have  become  more  highly  diffei-entiated  and  hence  more  stable. 
Regenerating  cells  ought  to  furnish  a  much  better  basis  than  old  ones. 
"We  find  however  that  there  is  no  striking  difference  in  the  two  cases. 
Regeneration  proceeds  at  approximately  the  same  rate  whether  old  or 
new  cells  have  furnished  the  basis  for  the  new  material.  It  is  true  that 
the  data  show  on  the  average  a  slight  advantage  in  favor  of  the  new 
tissue,  especially  during  the  early  periods,  but  this  advantage  is  small 
and  it  is  doubtful  Avhether  it  can  be  considered  as  significant.  There  is 
some  evidence  that  the  earliest  stages  of  regeneration,  those  due  to  cell 
migration  exclusively,  are  more  rapid  from  new  than  from  old  tissue. 
If  this  evidence  is  reliable  an  explanation  is  found  for  the  slight  advan- 
tage in  favor  of  the  new  tissue  at  later  periods. 

Summary 

1.  A  comparison  of  the  rate  of  regeneration  in  tadpoles  of  Raiia 
clamitans  in  eases  where  there  are  newly  regenerated  cells  at  the  cut 
surface  with  those  in  which  only  old  cells  are  present  shows,  on  the 
whole,  little  difference  between  the  two. 

2.  The  slight  difference  favors  the  new  cells  but  may  not  be 
significant. 

3.  In  Experiment  I  the  specific  length  of  regeneration  at  the 
end  of  6  days  was  0.196  from  old  tissue  and  0.204  from  new  tissue. 

4.  In  the  same  experiment  at  the  end  of  8  days  the  specific 
length  from  the  old  was  0.303  and  from  the  new  0.310. 

5.  In  Experiment  II  the  general  result  was  similar  to  that  in 
Experiment  I.  The  amounts  of  regeneration  in  the  two  cases  are  very 
nearly  equal  and  the  slight  difference  is  in  favor  of  the  new  tissue. 

6.  Experiment  III  shows  that  as  regards  completeness  of  regen- 


25]  RATE    OF    REGEXERATION—ZELENY  25 

eration  there  is  again  essential  similarity  between  the  old  tissue  and  the 
new  tissue  levels. 

7.  The  result  strengthens  the  view  that  the  rate  of  regeneration  is 
controlled  in  large  part  by  factors  not  inherent  in  the  character  or  con- 
dition of  the  cells  near  the  cut  surface. 

8.  In  the  case  of  the  earliest  stages,  those  in  which  there  is  cell 
migration  but  no  cell  division,  there  is  some  evidence  that  the  rate  of 
regeneration  may  be  greater  from  new  than  from  old  tissue. 


26  ILLIXOIS    BIOLOGICAL    MOXOGRAPHS  [26 


PART  II 

THE  EFFECT  OF  SUCCESSIVE  REMOVAL  UPON  THE  RATE 
AND  COMPLETENESS  OF  REGENERATION 

One  of  the  most  ioteresting  facts  in  connection  with  regeneration 
is  the  ability  to  replace  a  part  after  repeated  removal.  The  present  set 
of  experiments  was  made  in  continuation  of  jarevious  studies  of  the 
effect  of  successive  removal  upon  the  rate  of  regeneration  (Zeleny  1907, 
1908,  1909).  The  earlier  studies  show  that  as  a  rule  the  rate  of  regen- 
eration following  a  first  removal  is  no  greater  than  that  following  second 
and  latei^reuiovals  if  the  effect  of  age  is  eliminated.  Where  a  difference 
exists  it  seems  to  be  in  favor  of  the  later  regenerations. 

The  matter  is  of  very  great  interest  in  connection  with  general 
problems  of  development  and  particularly  in  connection  with  'the  ques- 
tion as  to  the  existence  or  non-existence  of  a  necessary  limit  to  the 
amount  of  living  substance  that  a  single  individual  may  produce  during 
its  life  cycle.  Does  the  production  of  a  group  of  tissues  use  up  a  part 
of  a  certain  store  of  developmental  energy  or  of  developmental  factors 
possessed  by  the  individual  or  is  this  store  inexhaiistible  or  perchance 
even  increased  by  exercise  of  the  functioia?  These  questions  warrant 
more  extended  study  especially  in  view  of  the  additional  analysis  that 
has  been  made  of  other  factors  controlling  the  rate  of  regeneration. 
The  paper  includes  all  the  unpublished  data  that  have  been  obtained 
on  the  problem  at  hand.  In  general  these  data  support  the  conclusions 
previously  reached.  The  descriptions  of  the  individual  experiments 
will  first  be  given  and  they  will  be  followed  bj-  a  discussion  of  the  general 
results. 

Experiment  I  Rana  clamitans  Skries  3628-3675 
Material  and  Method  The  tadpoles  were  collected  on  December  9, 
1911.  At  the  time  of  the  operation  on  December  20  the  average  total 
length  Avas  33.0  mm.  and  the  average  tail  length  21.6  mm.  Forty-eight 
individuals  were  divided  into  twelve  sets  of  four  each.  The  four  indi- 
viduals of  a  set  are  called  a,  h,  c,  and  d.  Approximately  one-half  in 
length  of  the  tail  was  removed  by  a  transverse  cut  in  c  and  d.  After 
21  days  the  regenerated  portion  of  the  tail  was  removed.  In  individual 
c  the  second  cut  came  inside  of  the  border  liue  between  old  and  new 


27]  RATE    OF    REGEKERATIOS —  ZELENY  27 

tissue  and  iu  individual  d  it  came  outside  of  that  liue.  Of  the  two  indi- 
viduals available  for  second  regeneration  in  each  set,  the  one  with  the 
cut  nearer  to  the  tip  of  the  tail  was  chosen  as  individual  c  and  the  other 
as  individual  d.  In  this  way  the  second  regeneration  levels  were  equal- 
ized. A  first  removal  of  a  half  of  the  tail  was  made  in  individuals  a 
and  h  at  the  same  time  that  the  second  removal  was  made  in  c  and  d. 
A  direct  comparison  of  the  rate  of  the  second  regeneration  with  that 
of  the  first  was  thus  made  possible  without  the  complication  due  to 
internal  factors  such  as  difference  in  age,  or  external  factors  such  as 
temperature  and  food. 

Measurements  of  regenerated  lengths  were  made  at  the  end  of 
six  and  of  eight  days,  other  experiments  having  shown  that  the  period 
of  most  rapid  growth  comes  at  about  this  time. 

Elsewhere  there  is  a  comparison  of  the  rate  of  regeneration  from 
new  tissue  with  that  from  old  tissue.  Here  the  chief  concern  is  the 
comparison  of  the  rate  of  the  second  regenerations,  including  both  old 
tissue  and  new  tissue  levels,  with  first  regenerations. 

Data  The  results  of  the  experiment  are  given  in  Table  19  for  six- 
day  regenerations  and  in  Table  20  for  eiglit-day  regenerations.  At  the 
end  of  six  days  the  average  length  of  first  regenerations  is  2.01  mm. 
and  of  second  regenerations  2.18  mm.  Tlie  first  exceeds  the  second  in 
two  cases,  the  second  exceeds  the  first  in  eight  and  one  is  tied.  The 
corresponding  average  specific  amounts  are  0.194  and  0.205.  In  five 
eases  the  first  exceeds  the  second  and  in  six  the  second  exceeds  the  first. 

At  eight  days  the  average  length  of  the  first  regenerations  is  3.06  mm. 
and  of  the  second  3.42  mm.  The  first  exceeds  the  second  iu  three  sets 
and  the  second  exceeds  the  first  in  seven  sets.  The  corresponding  aver- 
age specific  amounts  are  0.298  and  0.323.  In  four  the  first  exceeds  the 
second  regeneration  and  in  six  the  second  exceeds  the  first. 

Compai'ing  the  first  regenerations  on  the  one  hand  with  second 
regenerations  from  old  tissue  and  on  the  otlier  hand  with  second  regen- 
erations from  new  tissue  it  is  found,  including  only  complete  sets,  that 
at  the  end  of  six  days  the  average  first  regeneration  length  is  2.01  mm. 
while  that  of  the  second  from  new  tissue  is  2.15  mm.  and  from  old  tissue 
2.16  mm.  The  corresponding  average  specific  amounts  are  0.194  for 
first  regenerations  and  0.196  for  second  regenerations  from  old  tissue 
and  0.204  for  second  regenerations  from  new  tissue. 

At  eight  days  the  first  regeneration  lengths  average  3.06  mm.  while 
second  regenerations  from  old  tissue  average  3.19  and  those  from  new 
tissue  3.12.  The  corresponding  specific  lengths  are  0.298  for  first  regen- 
erations and  0.303  for  second  from  old  tissue  and  0.310  for  second  from 
new  tissue. 


28  ILLINOIS    BIOLOGICAL    MOXOGRAFHS 

TABLE  19 

Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

Six  Days 


[28 


Series 

Regen- 
eration 

Total 
length 

Tail 
length 

Length 
moved 

l.engtl- 
re  gen 
erated 

Specific 
length 
regen 
erated 

Aver- 
age 
length 
regen- 
erated 

Aver- 
age 
speci6c 
length 

regen- 
erated 

1 

individual  a 

35.5 

23.1 

11.5 

1.9 

0.17 

^ 

individual  b 

34.5 

21.9 
24.1 

9.4 

1.8 
2.2 

0.19 

1.85 

0.180 

2 

c  from  old  tissue 

38.0 

13.2 

0.17 

d  from  new  tissue 

39.2 

24.6 

12.8 

2.3 

0.18 

2.25 

0.175 

' 

1 

a 
b 

34.5 
33.9 

23.0 
22.2 

' 

' 

' 

' 

II 

9.6 

1.7 

0.18 

1.70 

O.ISO 

2 

c  old 

35.7 

23.2 

12.3 

2.0 

0.16 

d  new 

33.8 

22.1 

10.2 

1.8 

0.18 

1.90 

0.170 

1 

a 

36.2 

23.3 

9.7 

1.7 

0.18 

b 

34.1 

22.5 

10.9 

1.9 

0.17 

1.80 

0.175 

III 

2 

c   old 

35.S 

23.1 

12.8 

2.0 

0.16 

d  new 

38.4 

25.0 

11.9 

2.4 

0.20 

2.20 

0.180 

1 

a 

33.1 

21.2 

12.6 

'2.-2- 

0.17 

b 

32.4 

20.8 

10.2 

1.7 

0.17 

1.95 

0.170 

IV 

J 

2 

c  old 

32.9 

20.8 

11.3 

1.7 

0.15 

d  new 

31.4 

20.4 

9.3 

2.2 

0.24 

1.95 

0.195 

1 

a 

40.8 

27.3 

11.9 

2.1 

0.18 

b 

39.4 

26.4 

12.7 

2.2 

0.17 

2.15 

0.175 

V 

2 

c   old 

37.5 

23.8 

11.5 

2.2 

0.19 

d  new 

42.8 

29.2 

15.1 

2.3 

0.15 

2.25 

0.170 

1 

a 

37.0 

24.5 

10.2 

1.9 

0.19 

b 

35.7 

24.6 

12.9 

2.2 

0.17 

2.05 

0.180 

VI 

2 

c  old 

37.0 

25.6 

11.2 

2.3 

0.21 

d  new 

35.9 

23.3 

9.9 

2.1 

0.21 

2.20 

0.210 

1 

a 

31.2 

20.1 

11.9 

2.1 

0.18 

b 

28.0 

18.6 

8.4 

2.0 

0.24 

2.05 

0.210 

VII 

2 

c   old 

31.3 

20.8 

— 

d  new 

29.0 

19.2 

9.2 

2.4 

0.26 

2.40 

0.260 

29] 


RATE    OF    RECEXERATIOX—ZELEXy 


29 


TABLE  19   (Contiuued) 


Series 

1 
Re«en- 

eration 

1 

VIII 

2 

1 

IX 

2 

1 

X 

2 

1 

XI 

2 

1 

XII 

2 

1 

Average 

2 

a 

b 

c 

old 

d 

new 

a 

b 

c 

old 

d 

new 

a 

b 

c 

old 

d 

new 

a 

b 

c 

old 

d 

new 

a 

b 

c 

old 

d 

new 

Total 
length 

Tail 
length 

Length 

re- 
moved 

Length 
regen. 
erated 

Specific 
length 
regen- 
erated 

.\ver- 
age 
length 
regen- 
erated 

28.7 

32.0 

18.5 
21.5 

21.1 
22.0 

10.0 
8.5 

2.1 
2.2 

2.4 
2.7 

0.21 
0.26 

2.17 

31.8 
33.0 

13.2 
11.7 

0.18 

0.23 

2.55 

29.8 
26.9 

19.1 

17.0 

10.1 
10.7 

2.3 
2.3 

0.23 
0.22 

2.30 

26.5 
29.4 

17.0 
19.0 

9.6 

8.7 

2.5 
2.0 

0.26 
0.23 

2.25 

32.1 
32.4 

21.5 
21.5 

22.4 
19.8 

12.0 
10.1 

2.3 
2.0 

0.19 
0.20 

2.15 

32.7 
30.0 

— 

30.9 
30.1 

20,9 
20.2 

10.2 
9.4 

2.0 
1.8 

0.20 
0.20 

1.90 

31.1 
32.4 

20.8 
21.8 

9.2 
8.9 

1.6 
1.8 

0.17 
0.20 

1.70 

28.0. 
26.3 

18.0 
16.4 

11.0 
10.4 

2.2 
2.1 

0.20 
0.20 

2.15 

24.4 
28.5 

15.4 
18.1 

8.6 
8.7 

2.7 
1.9 

0.31 
0.22 

2.30 

32.7 

21.4 

10.6 

2.01 

33.4 

21.8 

10.9 

2.18 

0.185 


0.265 
0Tl94 


The  data  as  a  whole  show  an  advantage  in  favor  of  the  second 
regeneration  as  compared  with  the  first.  This  is  seen  not  only  when  the 
direct  regenerated  lengths  are  taken  but  also  when  the  specific  amounts 
are  used.  Elsewhere  it  is  shown  that  the  specific  amount  of  regeneration 
is  independent  of  the  level  of  the  cut  and  therefore  a  constant  within 
the  limits  of  removal  as  used  in  this  experiment.     The  specific  amount 


30 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[30 


determinations  are  therefore  more  accurate  for  our  purposes  than  the 
direct  values  of  length  regenerated. 

Tlie  first  regeneration  is  slight!}'  below  the  second  not  only  in  case 
the  latter  is  from  new  cells  but  also  in  case  it  is  from  old  cells.  The 
difference  between  first  and  second  regenerations  therefore  can  not  be 
due  entirely  to  the  presence  in  the  former  of  cells  wliicli  are  already 
undergoing  regeneration. 

TABLE  20 

Rana  clamitans       Series  3628-3675 

First  and  second  regenerations  compared       Age  factor  eliminated 

Eight  days 


Re- 
gener 
ation 

Length 
removed 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

.\verage 
length 
regen- 
erated 

Average 
specific 
length 
regen- 
erated 

1 

individual  a 

11.5 

3.1 

0.26 

individual  b 

9.4 

2.5 

0.27 

0,28 

0.265 

2 

c  from  old  tissue 

13.2 

3.5 

0.27 

d  from  new  tissue 

12.8 

3.1 

0.24 

3.30 

0.255 

1 

a 

— 

' 

b 

9.6 

2.1 

0,22 

2.10 

0.220 

2 

c   old 

12.3 

3.4 

0.28 

d  new 

10.2 

— 

3.40 

0.280 

1 

a 

9.7 

2.7 

0.28 

b 

10.9 

3.4 

0.31 

3.05 

0.295 

2 

c  old 

12.8 

3.25 

0.25 

d  new 

11.9 

3.5 

0.29 

3.37 

0.270 

1 

a 

12.6 

3.25 

0.26 

2 

b 

10.2 

3.25 

0.32 

3.25 

0,290 

c  old 

11.3 

3.4 

0.30 

d  new 

9.3 

— 

3.40 

0.300 

1 

a 

11.9 

— 

2 

b 

12.7 

4.0 

0.31 

4.00 

0.310 

c  old 

11.5 

— 

d  new 

15.1 

— 

31] 


RATE    OF    REGEXERATION—ZELEXV 
TABLE  20    (Continued) 


Series 

Re- 
gener- 
ation 

Length 

Length 
regen- 
erated 

Specific 
length 
regen- 
erated 

.•\veragc 
length 
regen- 
erated 

Average 
specific 
length    , 
regen- 
erated 

1 

a 

10.2 

3.6 

0.35 

VI 

b 

12.9 

3.6 

0.28 

3.60 

0.315 

2 

c   old 

11.2 

3.1 

0.28 

d  new 

9.9 

3.1 

0.31 

3.10 

0.295 

1 

a 

11.9 

3.8 

0.32 

VII 

b 

8.4 

3.25 

0.39 

3.52 

0.355 

2 

c   old 

— 

d  new 

9.2 

3.6 

0.39 

3.60 

0.390 

1 

a 

10.0 

3.25 

0.32 

VIII 

b 

8.5 

3.4 

0.40 

3.32 

0.360 

2 

c  old 

13.2 

— 

d  new 

11.7 

4.9 

0.42 

4.90 

0.420 

1 

a 

10.1 

3.2 

0.32 

b 

10.7 

3.4 

0.32 

3.30 

0.320 

IX 

2 

c  old 

9.6 

3.5 

0.36 

d  new 

8.7 

3.0 

0.34 

3.25 

0.350 

1 

a 

12.1 

3.6 

0.30 

b 

10.1 

2.3 

0.23 

2.95 

0.265 

X 

2 

c  old 

— 

d  new 

— 

1 

a 

10.2 

3.5 

0.34 

b 

9.4 

2.5 

0.27 

3.00 

0.305 

XI 

2 

c  old 

9.2 

2.3 

0.25 

d  new 

8.9 

2.5 

0.28 

2.40 

0.265 

1 

a 

11.0 

— 

b 

10.4 

2.7 

0.26 

2.70 

0.260 

XII 

2 

c  old 

8.6 

3.5 

0.41 

d  new 

8.7 

3.5 

0.40 

3.50 

0.405 

Average 

1 

10.6 

3.06 

0.298 

2 

10.9 

3.42 

0.323 

32  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [32 

Experiment  II       Rana  clamitans      Series  3676-3765 

Material  and  Method  Ninety  tadpoles  with  an  average  total  length 
of  about  40  mm.  and  an  average  tail  length  of  27  mm.  were  used  in  the 
experiment.  The  plan  consisted  in  the  removal  of  a  portion  of  the  tail 
in  a  part,  S,  of  the  individuals,  the  remaining  part,  F,  being  left  un- 
injured at  the  time.  After  S  had  been  regenerating  a  new  tail  for 
twenty-two  days  both  S  and  P  were  operated  upon.  In  S  the  regen- 
erating tails  were  removed  by  a  cut  which  came  at  the  border  line  be- 
tween the  old  and  the  new  tissues.  In  P  an  operation  was  made  similar 
to  the  original  one  on  S  and  leaving  the  same  amount  of  old  tail  in  both 
S  and  P.  The  procedure  is  similar  to  that  shown  in  Pigure  1.  S  and 
P  were  now  allowed  to  regenerate  and  a  direct  comparison  is  possible 
between  a  second  regeneration  in  S  and  a  first  regeneration  in  P. 

Measurements  were  made  of  regenerated  lengths  at  4,  6,  8,  10,  12^, 
18  and  56  days.  The  operations  were  made  at  six  levels  corresponding 
approximately  to  the  removal  respectively  of  ^/jg,  ^/iqi  %>  %>  V2 
and  %  of  the  tail.  Pour  of  these  levels,  ^/jq)  %,  V2  ^^^  73;  had  at 
least  five  individuals  each  for  each  regeneration.  The  other  two  levels, 
^/jg  and  Vfe.  tad  less  than  five  individuals  per  regeneration  but  are 
included  in  the  tables  though  their  averages  are  not  as  reliable  as  those 
of  the  others. 

The  method  as  described  agrees  in  principle  with  that  pursued  in 
Experiment  I.  It  has  a  decided  advantage  over  a  direct  comparison 
within  a  single  individual  because  it  eliminates  the  age  factor  as  well  as 
the  effects  of  change  in  external  conditions  such  as  temperature  and 
food. 

Data  The  results  of  the  experiment  are  given  in  Tables  21  to  30 
and.  in  Pigures  2  and  3.  The  data  show  on  the  whole  a  tendency  for 
the  second  regeneration  to  remain  in  advance  of  the  first  for  eight  or 
ten  days  after  the  operation.  The  first  regeneration  then  catches  up 
and  even  slightly  surpasses  the  other;  this  is  apparent  both  when  the 
regenerated  lengths  are  taken  directly  and  when  they  are  corrected  for 
difference  in  level  of  the  cut  and  put  in  terms  of  specific  regenerated 
length  or  the  length  regenerated  per  unit  of  removed  length. 

In  making  the  comparisons  certain  general  features  must  be  borne 
in  mind.  The  maximum  rate  of  regeneration  is  reached  on  or  near  the 
seventh  day,  earlier  for  the  smaller  removals  and  later  for  the  larger 
removals.  The  whole  regeneration,  in  so  far  as  it  is  completed,  is 
finished  in  nearly  all  cases  at  I2I/2  days,  again  somewhat  earlier  for  the 
smaller  and  somewhat  later  for  the  larger  removals.  In  the  tadpoles 
used  in  the  present  experiment  about  four-tenths  in  length  of  the  re- 
moved tail  is  replaced  before  regeneration  stops.    This  was  found  to  be 


33] 


RATE    OF    REGENERATION— ZELENY 


33 


generally  true  of  tadpoles  of  this  size  in  Rana  clamitans.  The  percent 
regenerated  is  somewhat  greater  for  the  smallest  removals  than  for  the 
others.  After  the  maximum  is  reached  there  is  a  tendency  toward  de- 
crease of  the  regenerated  region  though  this  is  hard  to  determine  with 
accuracy  because  the  boundarj-  between  old  and  new  tissue  becomes 
more  and  more  obscure  as  time  goes  on.  For  this  reason  the  data  for 
56  days  of  regeneration  are  not  as  reliable  as  the  others. 


4  6  8         10  121/2  18 

— >-      Days 
Figure  2.    Specific  regenerated  lengths  during  the  regenerative  period  for 
both  first  and  second  regenerations.     Tadpole  tail  of    Rana  clamitans.      Series 
3676-3765. 

Broken  line  =  second   regeneration. 
Unbroken  line  =  first  regeneration. 


2  5         7  9         ll',4  15% 

— >-      Days 
Figure  3.    Change  in  specific  rate  of  regeneration  during  the  regenerative 
period  for  both  first  and  second  regenerations.    Tadpole  tail  of  Rana  clamitans. 
Series  3G76-3765. 

Unbroken  line  =  first  regeneration. 
Broken   line  =  second   regeneration. 


34  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [34 

At  the  four-day  period  the  amount  of  regeneration  is  so  small  that 
there  is  a  large  probable  error  and  these  data  should  be  used  with  cau- 
tion. For  the  ^/jg  and  %  removals  the  number  of  individuals  is  so 
small  that  the  data  for  these  levels  do  not  compare  in  accviracj'  with  the 
others  and  they  will  therefore  be  passed  over  for  the  present. 

The  data  are  presented  in  Tables  21  to  30.  Tables  21  to  26  give 
respectively  the  regenerations  for  tlie  six  different  levels  beginning  with 
the  shortest  removal.  Table  27  collects  all  the  data  of  amounts  regen- 
erated and  Table  28  aU  the  data  of  specific  amounts  regenerated. 
Figure  2  gives  in  graphic  form  the  specific  amounts  regenerated 
for  each  regeneration.  Table  29  gives  the  differences  between 
the  first  and  second  regenerations  for  each  of  the  different  levels  at  each 
of  the  seven  times  of  measurement.  It  includes  the  differences  in  specific 
length  as  well  as  those  in  absolute  length.  The  specific  lengths  furnish 
the  better  basis  for  comparison  and  will  be  used  in  the  following  discus- 
sion unless  otherwise  stated.  Table  30  compares  the  specific  rates  in 
the  first  and  second  regenerations  and  Figure  3  gives  the  results  in 
graphic  form. 

Taking  ujj  the  regeneration  from  the  different  levels  and  leaving 
out  of  consideration  for  the  present  the  two  levels  with  too  small  a 
number  of  individuals,  the  data  for  the  ^/^  level  as  given  in  Table  4 
are  the  first  to  be  considered.  There  are  five  individuals  for  first  and 
seven  for  second  regenerations.  The  second  regeneration  is  ahead  in 
specific  length  from  the  fourth  to  the  tenth  daj'.  At  12i/o  days  the  two 
are  tied  and  at  .56  days  the  first  is  ahead.  Eegeneration  is  completed  in 
121/2  days  and  beyond  this  time  there  is  a  decrease  in  regenerated  ma- 
terial. The  decrease  is  greater  in  the  second  than  in  the  first  regenera- 
tion, hence  the  ascendency  of  the  latter  at  56  days.  During  the  Avhole 
period  of  active  regeneration  the  second  regeneration  remains  ahead. 

There  are  eight  individuals  for  the  first  regeneration  and  eleven  for 
the  second  at  the  %  level  (Table  24).  The  specific  amounts  of  regenera- 
tion are  strikingly  similar  throughout  the  whole  period  of  regeneration. 
The  two  departures  from  equality  are  an  advantage  of  0.01  for  the  second 
regeneration  at  8  daj'S  and  a  disadvantage  of  0.02  at  IS  days.  These 
■departures  are  in  the  direction  of  the  general  rule  observed  at  other 
levels  that  the  second  regeneration  tends  to  be  ahead  at  the  earlier  pe- 
riods and  the  first  at  later  periods,  the  advantage  in  the  later  case  being 
due  to  the  earlier  completion  of  regeneration  and  absorption  of  regener- 
ated material  in  the  second  regenerations  than  in  the  first  ones.  In  this 
instance  the  first  regeneration  does  not  gain  an  advantage  until  after  the 
second  has  reached  its  maximum. 

At  the  1/2  level  there  are  5  individiials  for  the  first  regeneration  and 
8  for  the  second  (Table  25).    The  second  is  ahead  until  the  eighth  day. 


35]  RATE    OF    REGENERATION— ZELEXY  35 

Begiuniug  with  the  tenth  day  the  first  is  ahead.  In  general  the  advan- 
tage of  the  first  increases  as  time  goes  on.  The  growth  of  new  tissue 
does  not  terminate  until  the  eighteenth  day  or  after. 

At  the  ^3  level  there  are  five  individuals  for  the  first  and  tea  for 
the  second  regeneration  (Table  26).  The  second  is  ahead  of  the  first 
until  the  tenth  day,  after  which  the  first  is  in  the  lead.  Regeneration 
is  not  stopped  until  the  eighteenth  day  or  later. 

At  all  four  of  these  levels  the  specific  length  of  the  second  regen- 
eration tends  to  be  ahead  until  the  tenth  day  (Table  28  and  Figure  2). 
The  maximum  rate  of  regeneration  is  reached  before  this  time  and  some- 
what earlier  by  the  second  than  by  the  first  regeneration,  hence  the 
relative  gain  by  the  latter  after  the  tenth  day  (Table  30  and  Figure  3). 
The  stopping  of  regeneration  also  comes  earlier  for  the  second  than  for 
the  first  regeneration  as  does  the  beginning  of  absorption  of  regenerated 
material. 

The  data  in  Experiment  I  concern  the  amount  of  regeneration  at 
six  and  at  eight  daj's.  At  the  corresponding  times  in  Experiment  II 
the  second  regeneration  is  ahead  of  the  first.  There  is  a  full  agreement 
between  the  two  experiments  in  this  regard. 

The  more  rapid  rate  of  the  second  regeneration  at  the  start  may 
at  first  sight  seem  to  be  due  to  the  presence  of  at  least 
some  cells  which  have  been  actively  engaged  in  previous  regenerations. 
If  the  second  cut  comes  outside  of  the  boundary  between  old  and  new 
cells  the  latter  cover  the  whole  new  cut  surface.  Even  if  the  cut  seems 
to  be  exactly  at  the  original  cut  level  there  will  be  some  new  cells  at 
the  regenerating  surface.  These  cells  which  are  already  regenerating 
may  be  expected  to  adjust  themselves  more  readily  to  the  new  conditions 
than  old  ones  which  have  not  been  engaged  in  such  a  process.  In  another 
place  the  relative  rates  from  old  and  from  new  tissue  are  described 
and  a  .slight  early  difference  favoring  the  new  tissue  is  made  out.  While 
tliis  slight  initial  advantage  may  be  explained  in  this  way  it  is  probably 
confined  to  the  period  of  cell  migration  and  is  not  a  factor  in  the  period 
of  cell  di\'ision  which  begins  on  the  second  day  or  later.  It  is  evident 
that  on  the  wliole  the  control  of  rate  is  not  a  matter  inherent  in  the 
cells  in  the  neighborliood  of  the  cut  surface.  Indications  point  rather 
to  a  more  central  control  of  the  process. 


36 


ILLINOIS    BIOLOGICAL    MOXOGRAPHS 


1 36 


TABLE  21 

Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

One-eighteenth  of  tail  removed 


Catalog 
number 

Re- 
moved 
lengtb 

1.4 
1.7 

1.5 

1.3 
1.6 
1.6 
1.6 

1.5 

Length   regenerated  in  mm. 

4 
Days 

0.24 
0.30 

6 
Days 

8 
Days 

10 
Days 

1.0 

0.8 

m 

Days 

18 
Days 

56 

Days 

First 

3706 
3742 

0.54 
0.40 

0.9 
0.7 

1.0 
0.9 

0.9 
0.9 

0.7 
0.7 

eration 

Average 

Second 
regen- 
eration 

3676 
3682 
3730 
3754 

0.27 
0.18 
0.39 
0.06 

0.60 
0.60 
0.75 
0.55 

0.9 
0.9 
0.9 
0.9 

1.0 
1.0 
0.9 
1.1 

1.0 
1.0 
0.9 
1.2 

1.0 
1.0 
0.9 
1.2 

0.7 
1.1 
0.7 
1.1 

Average 

Av.  length— 

-First  regen. 

0.27 

0.47 

0.8 

0.9 

0.9 

0.9 

0.7 

Av.  length- 

-Second  regen. 

0.22 

0.62 

0.9 

1.0 

+0.1 

1.0 

1.0 

0.9 

Increase  or 

decrease 

—0.05 

-fO.15 

+0.1 

+0.1 

+0.1 

+0.2 

Specific  Ig.- 

—First  regen. 

0.17 

0.30 

0.53 

0.58 
0.67 

0.61 

0.60 

0.67 

40.07 

0.45 

Speciflc  Ig.- 

-Second  regen. 

0.15 

0.42 

+0.12 

0.60 

0.67 

0.60 

Increase  or 

decrease 

—0.02 

+0.07 

+0.09 

4  0.06 

4  0.15 

37] 


RATE    OF    REGENERATION  — ZELEWy 


TABLE  22 

Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

One-tenth  of  tail  removed 


Catalog 
number 

Re- 
moved 
length 
mm. 

2.5 

Length   regenerated 

in  mm. 

4 
Days 

6 
Days 

8 
Days 

10 
Days 

12J 
Days 

18 
Days 

56 
Days 

3688 

0.12 

0.3 

0.3 

0.7 

0.9 

0.9 

0.7 

3707 

3.2 

0.24 

0.8 

1.1 

1.4 

1.4 

1.3 

0.7 

First 

3724 

2.6 

0.06 

0.5 

o.s 

1.1 

1.4 

1.4 

1.2 

regen- 

3743 

2.5 

0.03 

0.1 

0.4 

0.8 

1.0 

1.0 

1.7 

eration 

3760 

3.1 
2.6 

0.30 

0.6 

0.9 

1.1 

1.2 

1.1 

1.1 

Average 

3677 

2.0 

0.30 

0.6 

0.9 

0.9 

0.9 

0.9 

0.7 

3696 

2.1 

0.48 

0.8 

1.0 

1.1 

1.0 

1.0 

0.7 

3713 

2.8 

0.36 

0.8 

0.9 

0.9 

0.9 

0.9 

0.5 

Second 

3719 

3.1 

0.36 

0.8 

1.1 

1.4 

1.4 

1.3 

— 

regen- 

3749 

2.8 

0.30 

0.6 

1.2 

1.4 

1.4 

1.3 

0.9 

eration 

3750 

3.5 

0.48 

1.3 

1.7 

1.9 

2.0 

2.0 

— 

3701 

3.2 
2.8 

0.42 

0.8 

1.1 

1.2 

1.3 

1.3 

— 

Average 

Av.  length- 

-First  regen. 

0.15 

0.5 

0.7 

1.0 

1.2 

1.1 

1.1 

Av.  length- 

-Second  regen. 

0.39 

0.8 

1.1 
+0.4 

1.3 

1.3 
+0.1 

1.2 

0.8 

Increase   or 

decrease 

-fO.24 

+0.3 

+0.3 

+0.1 

—0.3 

Specific  Ig.- 

-First  regen. 

0.06 
0.14 

0.18 

0.27 

0.39 

-fO.IZ 

0.38 

0.46 

0.42 

0.42 

Specific  Ig.- 

—Second  regen.  , 

0.30 
+0.12 

0.46 

0.46 

0.43 

0.29 

Increase  or 

decrease 

^  0.08 

i  0.08 

0.00 

+0.01 

—0.13 

38 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[38 


TABLE  23 

Rana  elamitans       Series  3676-3765 

Comparison  of  first  and  second  regeneration      Age  factor  eliminated 

One-sixth  of  tail  removed 


Catalog 
number 

Re- 
moved 
length 

5.3 

Length   regenerated   in   mm. 

4 
Days 

0.54 

6 
Days 

1.2 

8 
Days 

10 
Days 

12i 
Days 

18 
Days 

S6 
Days 

3708 

1.9 

2.1 

2.3 

2.3 

1.8 

First 

3726 

4.3 

0.42 

0.9 

1.3 

1.4 

1.4 

1.4 

1.4 

regen- 

3762 

4.1 

0.57 

1.0 

1.2 

1.5 

1.7 

1.8 

1.4 

eration 

Average 

4.6 

3678 

5.0 

0.20 

0.5 

0.9 

1.0 

1.1 

1.1 



3684 

5.5 

0.15 

0.7 

1.2 

1.4 

1.4 

1.5 

1.4 

Second 

3702 

4.7 

0.42 

0.8 

1.1 

1.3 

1.3 

1.3 

1.3 

regen- 

3720 

4.6 

0.06 

0.3 

1.3 

1.8 

2.3 

1.9 

2.0 

eration 

3756 

4.8 
4.9 

0.36 
0.51 

1.0 

1.3 

1.7 

1.8 

1.6 

— 

Average 

Av.  length— 

-First  regen. 

1.0 

1.5 

1.7 

1.8 
1.6 

1.8 

1.5 

Av.  length — 

Second  regen. 

0.24 

0.7 

1.2 

1.4 

1.5 

1.6 

Increase  or 

decrease 

—0.27 

—0.3 

—0.3 
0.33 

—0.3 

—0.2 

—0.3 

+0.1 

Specific  Ig  — 

-First  regen. 

0.11 



0.05 

0.22 

0.37 
0.29 

0.39 

0.39 

0.34 

Specific  Ig  — 

-Second  regen. 

0.14 

0.24 

0.33 

0.31 

0.33 

Increase  or 

decrease 

—0.06 

—0.08 

—0.09 

—0.08 

—0.06 

—0.08 

—0.01 

39] 


R.-^ITE    OF    REGEXERATIOX  —  ZELEXY 


39 


TABLE   24 

Rana  clamitaiis       Series  3676-3765 
Compai'ison  of  first  and  second  regenerations       Age  factor  eliminated 
One-tliird  of  tail  removed 


Catalog 
number 

Re- 
moved 
length 

1. 

ngth   regenerated 

in  mm. 

4 
Days 

6 

Days 

S 
Days 

10 
Days 

12} 
Days 

18 
Days 

56 
Days 

3690 

9.7 

0.48 

1.0 

1.7 

2.4 

2.6 

2.7 

2.2 

3709 

8.8 

0.48 

1.3 

2.0 

2.6 

3.2 

3.4 

3.3 

3727 

8.3 

0.48 

1.1 

1.6 

2.0 

2.2 

2.2 

2.2 

First 

3745 

10.0 

0.54 

1.8 

2.4 

3.8 

4.4 

4.8 

4.2 

regen- 

3744 

6.0 

0.36 

1.0 

1.3 

1.7 

1.8 

1.7 

— 

eration 

3761 

6.6 

0.39 

1.0 

1..-. 

1.9 

2.2 

2.3 

1.8 

3763 

8.5 

0.57 

1.1 

l.S 

2.4 

2.9 

3.1 

— 

3689 

6.3 

0.30 
0.30 

0.7 

1.2 

1.5 

1.6 

1.7 

1.4 

Average 

8.2 

3679 

8.4 

0.7 

1.4 

1,9 

1.9 

2.1 

— 

3685 

9.3 

0.60 

1.2 

1.9 

2.3 

2.8 

3.0 

2.6 

3697 

7.3 

0.48 

1.2 

1.7 

2.2 

2.4 

2.3 

2.1 

3703 

9.3 

0.45 

1.3 

2,0 

2.5 

2.6 

2.5 

2.5 

3715 

7.9 

0.24 

0.9 

1.7 

2.3 

2.6 

2.6 

2.8 

Second 

3721 

8.7 

0.57 

1.3 

1.9 

2.3 

2.6 

2.3 

2.2 

regen- 

3733 

8.5 

0.36 

1.0 

1.9 

2.4 

2.6 

2.6 

2.8 

eration 

3734 

8.5 

0.48 

2.1 

3.1 

4.5 

5.7 

6.4 

6.6 

3739 

9.6 

0.36 

1.0 

l.S 

2.4 

3.0 

2.9 

— 

3751 

6.7 

0.45 

1.1 

1,7 

2.1 

2.4 

2.5 

2.3 

3757 

8.0 
8.4 

0.42 

1.2 

2.1 

2.8 

3.1 

3.2 

3.1 

Average 

1.1 

Av.  length- 

-First  reg 

en. 

0.45 

1.7 

2.3 

2.6 

2.7 

2.5 

Av.  length- 

-Second  re 

gen. 

0.42 

1.1 

1.8 

2.3 

2.6 

2.6 

2.5 

Increase  or 

decrease 

—0.03 

0.0 

+0.1 

0.0 

0.0 

—0.1 

0.0 

Specific  Ig.- 

—First  reg 

en. 

0.05 

0.13 

0.21 

0.28 

0.31 

0.33 

0.30 

Specific  Ig.- 

—Second  r 

egen. 

0.05 

0.13 

0.22 

0.28 

0.31 

0.31 

0.30 

Increase  or 

decrease 

0.00 

0.00 

+0.01 

0.00 

0.00 

—0.02 

0.00 

40 


ILLIXOIS    BIOLOGICAL    MOXOGKAPHS 


[40 


TABLE  25 

Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

One-half  of  tail  removed 


Catalog 
number 

Re- 
moved 
length 
mm. 

Length   regenerated 

in   mm. 

4 
Days 

6 
Days 

8 
Days 

10 
Days 

m 

Days 

18 
Days 

56 
Days 

3710 

12.3 

0.42 

1.8 

2.9 

3.7 

3.9 

3.9 

3.9 

3728 

12.8 

0.60 

1.7 

2.8 

3.9 

4.8 

5.4 

5.8 

First 

3746 

13.3 

0.54 

1.7 

2.4 

4.1 

5.7 

7.0 

6.8 

regen- 

3764 

14.6 

0.42 

1.3 

2.5 

4.2 

5.3 

6.8 

6.5 

eration 

3765 

12.2 

0.30 

1.5 

2.3 

3.2 

3.9 

4.5 

4.5 

Average 

13.0 

3686 

14.5 

0.60 

2.1 

3.4 

4.8 

5.3 

5.2 

— 

3698 

14.9 

0.50 

1.5 

3.3 

4.3 

5.0 

5.4 

5.4 

3704 

14.5 

0.45 

2.2 

3.3 

4.4 

5.2 

5.5 

5.4 

Second 

3716 

12.7 

0.39 

1.7 

2.4 

3.4 

4.2 

5.1 

4.4 

regen- 

3722 

12.5 

0.60 

1.6 

2.6 

3.6 

3.9 

3.5 

4.2 

eration 

3740 

13.9 

0.30 

1.1 

2.1 

3.0 

4.6 

5.6 

6.8 

3752 

12.2 

0.54 

1.7 

2.5 

3.4 

4.1 

4.0 

— 

3758 

11.0 
13.1 

0.60 

1.5 

2.2 

2.9 

3.6 

4.1 

4.9 

Average 

Av.  length— 

-First  regen. 

0.46 

1.6 
1.7 

2.6 

3.8 

4.7 

5.5 

5.5 

Av.  length- 

-Second  regen. 

0.50 

2.7 

3.7 

4.4 

4.8 
—0.7 

5.2 

Increase  or 

decrease 

-f0.04 

+0.1 

+  0.1 

—0.1 

—0.3 

—0.3 

Specific  Ig.- 

-First  regen. 

0.03 

0.12 

0.20 

0.29 

0.36 

0.42 

0.42 

Speciflc  Ig- 

-Second  regen. 

0.04 

0.13 
+0.01 

0.21 

0.28 

0.34 

0.37 

0.40 

Increase  or 

decrease 

+0.01 

+0.01 

-0.01 

—0.02 

-^0.05 

—0.02 

41] 


RATE    OF    REGESERATION  —  ZELEXY 


TABLE  26 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

Rana  clamitans       Series  3676-3765 

Two-thirds  of  tail  removed 


Catalog 
number 

Re- 
moved 
length 
mm. 

16.8 

Length  regenerated 

in   mm. 

4 
Days 

6 
Days 

8 

Days 

10 
Days 

12i 
Days 

18 

Days 

56 

Days 

3692 

0.51 

1.1 

2.2 

3.2 

4.3 

5.0 

5.2 

3693 

17.2 

0.48 

1.8 

3.3 

5.0 

6.5 

7.3 

6.6 

First 

3711 

17.0 

0.54 

1.8 

3.6 

5.6 

7.0 

7.7 

8.3 

regen- 

3729 

16.1 

0.48 

1.9 

3.3 

4.6 

5.5 

6.7 

6.4 

eration 

3749 

16.2 
16.7 
16.0 

0.54 

1.2 

2.7 

4.2 

5.6 

7.1 

7.8 

Average 

3680 

0.60 

1.9 

3.0 

4.2 

5.2 

6.4 

6.6 

3681 

21.2 

0.84 

3.0 

4.0 

5.6 

6.3 

7.3 

7.2 

3687 

19.7 

0.54 

3.6 

5.6 

6.0 

6.6 

7.0 

— 

3699 

21.0 

0.54 

2.2 

4.3 

5.9 

7.1 

7.5 

7.2 

Second 

3705 

17.6 

0.72 

2.0 

3.6 

4.8 

6.4 

6.2 

6.0 

regen- 

3717 

17.6 

0.42 

2.6 

3.6 

5.2 

6.0 

6.7 

6.4 

eration 

3723 

18.4 

0.30 

2.3 

3.7 

5.3 

6.5 

8.1 

8.3 

3735 

16.5 

0.48 

2.0 

3.4 

5.5 

6.5 

7.8 

8.0 

3741 

16.0 

0.30 

1.9 

3.0 

4.4 

5.8 

6.9 

7.0 

3753 

16.8 
18.1 

0.42 

2.0 

2.5 

3.8 

5.2 

6.4 

7.1 

Average 

0.51 

Av.  length- 

-First  regen. 

1.56 

3.02 

4.52 

5.78 

6.76 

6.86 

Av.  length- 

-Second  regen. 

0.52 

2.35 

3.67 

5.07 

6.16 

7.03 

7.09 

Increase  or 

decrease 

-rO.01 

+0.79 

+0.65 

+0.55 

+0.38 

+0.27 

+  0.23 

Specific  Ig.- 

—First  regen. 

0.03 
0.03 

0.09 
0.13 

0.18 
0.20 

0.27 

0.35 

0.40 

0.41 

Specific  Ig.- 

-Second  regen. 

0.28 

0.34 

0.39 

0.39 

Increase  or 

decrease 

0.00 

+0.04 

+0.02 

+0.01 

—0.01 

—0.01 

—0.02 

42 


ILLIXOIS    BIOLOGICAL    MOXOGRAPHS 


TABLE  27 

Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations       Age  factor  eliminated 

Average  lengtlis  regenerated  in  mm. 


Approx. 
fraction 
of  tail 
removed 

Re- 
gener- 
ation 

Number 
of 

individ- 
uals 

Average 
length 
removed 

.\verage    length    regenerated 

4 
Days 

6 
Days 

8 
Days 

1 i 

0.8 

0.9 
0.7 

10 
Days 

12i 
Days 

18 
Days 

56 
Days 

'/,« 

1 

2 

1.5 

0.3 

0.5 

0.9 

0.9 

0.9 
1.0 

0.7 

2 

4 

1.5 

0.2 

0.6 

1.0 

1.0 

.0.9 

'^u. 

1 

5 

2.6 

0.1 

0.5 

1.0 

1.2 

1.1 

1.1 

2 

7 

2.8 

0.4 

0.8 

1.1 
1.5 

1.3 

1.3 

1.2 

0.8 

V„ 

1 

3 

4.6 

0.5 

1.0 

1.7 

1.8 

1.8 
1.5 

1.5 

2 

5 

4.9 

0.2 

0.7 

1.2 
1.7 

1.4 

1.6 

1.6 

v.. 

1 

8 

8.2 

0.4 

1.1 

2.3 

2.6 

2.7 

2.5 

2 

10 

8.4 

0.4 

1.1 

1.8 
2.6 
2.7 

2.3 

2.6 

2.6 

2.5 

V, 

1 

5 

13.0 

0.5 
0.5 

1.6 

3.8 

4.7 

5.5 
4.8 

5.5 

2 

8 

13.1 

1.7 

3.7 

4.4 

5.2 

1 

5 

16.7 

0.5 

0.5 

1.6 

3.0 

4.5 

5.8 

6.8 

7.0 

6.9 

'■■■• 

2 

10 

18.1 

2.3 

3.7 

5.1 

6.2 

7.1 

43] 


RATE    OF    RECENERATIOX—ZELE.XY 


43 


TABLE   2S 
Rana  clamitans       Series  3676-3765 

Comparison  of  first  and  second  regenerations      Age  factor  eliminated 
Specific  lengths  regenerated 


.  Approx. 
fraction 
of  tail 
removed 

Re- 
gener- 
ation 

Number 

of 
individ- 
uals 

Average 
length 

-emoved 
in  mm. 

Specif 

c  length 

regene 

rated  in 

mm. 

4 
Days 

6 
Days 

8 
Days 

0.53 
0.60 
0.27 
0.39 
0.33 
0.24 
0.21 
0.22 
0.20 
0.21 
0.18 
0.20 

10 
Days 

12J 
Days 

18 
Days 

56 
Days 

•As 

1 

2 

1.5 

0.17 

0.30 
0.42 

0.58 

0.61 

0.60 

0.45 

2 

4 

1.5 

0.15 

0.67 

0.67 

0.67 

0.60 

'/,o 

1 

5 

2.6 

0.06 

0.18 
0.30 

0.38 

0.46 

0.42 

0.42 

2 

7 

2.8 

0.14 

0.46 

0.46 

0.43 

0.29 

•/« 

1 

3 

4.6 

0.11 

0.22 
0.14 

0.37 

0.39 

0.39 

0.34 

2 

5 

4.9 

0.05 

0.29 

0.33 

0.31 

0.33 

'/a 

1 

8 

8.2 

0.05 

0.13 
0.13 

0.28 

0.31 

0.33 

0.30 

2 

10 

8.4 

0.05 

0.28 

0.31 

0.31 

0.30 

•■/, 

1 

5 

13.0 

0.03 

0.12 
0.13 

0.29 

0.36 

0.42 

0.42 

2 

8 

13.1 

0.04 

0.28 

0.34 

0.37 

0.40 

% 

1 

5 

16.7 

0.03 

0.09 
0.13 

0.27 

0.35 

0.40 

0.41 

2 

10 

18.1 

0.03 

0.075 

0.077 

0.28 

0.34 
0.413 
0.408 
0.005 

0.39 
0.427 
0.413 
0.014 

0.39 

All  levels- 

Averac 

J  e— First 

0.173 
0.208 

0.287 
0.310 

0.362 

0.390 

All   levels- 

Avera 

je — Seco 

id 

0.377 

0.385 

First  ahead 

- 

- 

0.023 

0.015 

0.005 

Second  ahead 

0.002 

0.035 

- 

- 

44 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


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45] 


RATE    OF    REGEXERATIOS  —  ZELENY 


4S 


Rana  clamitans       Series  3676-3765 
Specific  rates  of  first  and  second  regenerations  during  each  of  tlie  time  periods 


Approx. 

Re- 
gener- 
ation 

Num- 
Der  of 
indi- 
viduals 

length 
removed 

Specific  rate  of  regeneration 

of    Uil 
removed 

0-4 
Days 

4-6 
Days 

6-8 
Days 

8-10 
Days 

10-12* 
Days 

121-18 
Days 

18-56 

Days 

^/.s 

1 
2 

2 

1.5 

0.042 

0.065 

0.115 

0.025 

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4 

1.5 

0.037 

0.135 

0.090 

0.035 

0.000 

0.000 

—0.002 

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1 
2 

5 

2.6 

0.015 

0.040 

0.045 

0.055 

0.040 

—0.007 

—0.001 

7 

2.8 

0.035 

0.080 

0.045 

0.035 

0.000 

—0.005 

—0.004 

"/« 

1 
2 

3 

4.6 

0.027 

0.055 

0.055 

0.020 

0.010 

0.000 

—0.001 

5 

4.9 

0.012 

0.045 

0.050 

0.025 

0.025 

—0.004 

0.001 

'U 

1 
2 

8 

8.2 

0.012 

0.040 

0.040 

0.035 

0.015 

0.004 

—0.001 

10 

8.4 

0.012 

0.040 

0.045 

0.030 

0.015 

0.000 

—0.000 

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2 

5 

13.0 

0.007 

0.045 

0.040 

0.045 

0.035 

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13.1 

0.010 

0.045 

0.040 

0.035 

0.030 

0.005 

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2 

5 

16.7 

0.007 

0.030 

0.045 

0.045 

0.040 

0.009 

-1-0.000 

10 

IS.l 

0.007 

0.050 

0.035 

0.040 

0.030 

0.009 

0.000 

All  levels — Average — First 

0.018 

0.046 

0.057 

0.037 

0.026 

0.002 

—0.001 

All  levels — Average — Second 

0.019 

0.066 

0.051 

0.033 

0.017 

0.001 

—0.001 

First  ahead 

0.006 

0.004 

0.009 

0.001 

Second  ahead 

0.001 

0.020 

46  ILLINOIS    BIOLOGICAL    MOXOGRAPHS  [46 

Experiment  III      Amblystoha  punctatum       Series  3962-3999 

Material  and  Method  Eggs  of  Amblystoma  puoctatum  in  the  cleav- 
age stages  were  collected  on  Marcli  18,  1913,  and  hatched  in  the  labo- 
ratory on  April  9.  The  first  operations  were  made  on  April  23, 
at  which  time  also  five  controls  were  killed  and  preserved.  These  when 
measured  gave  an  average  total  length  of  13.1  mm.  and  an  average  tail 
length  of  5.3  mm.  Ninety  individuals  were  used  for  the  regeneration 
study.  In  thirty  individuals  two-thirds  in  length  of  the  tail  was  re- 
moved on  April  23.  The  regenerated  portion  in  these  was  removed 
on  May  10  and  at  the  same  time  in  a  second  thirty  individuals  two- 
thirds  of  the  tail  was  removed.  On  May  21  the  first  thirty  were 
operated  on  for  the  third  time,  the  second  thirty  for  the  second  time, 
and  the  third  thirty  for  the  first  time.  To  insure  as  accurate  a  compari- 
son as  possible  the  ninet.y  individuals  though  they  were  approximately 
of  equal  size  were  divided  into  thirty  groups  of  three  each,  a  selection 
being  made  so  that  the  three  members  of  a  group  were  as  much  alike 
as  possible.  In  each  group  one  of  the  tliree  members  was  used  for  the 
first  regeneration,  one  for  tlie  second  and  the  third  for  the  third  regen- 
eration. This  procedure  gave  a  possibility  of  comparing  the  first,  second 
and  third  regenerations  without  error  due  to  difference  in  size,  age,  or 
in  external  conditions. 

Three  individuals  from  each  thirtj-  were  killed  two  days  after  the 
last  operations,  four  in  four  days,  five  in  six  days,  five  in  eight  days, 
six  in  ten  da.ys  and  seven  in  fourteen  days. 

At  the  end  of  the  experiment,  control  individuals  gave  an  average 
total  lengtli  of  31.5  mm.  and  an  average  tail  lengtli  of  10.5  mm. 

Data  The  data  are  given  in  Tables  31  and  32.  The  specific  amounts 
of  regeneration  were  not  determined  because  the  removed  lengths  were 
alike  and  hence  the  comparison  of  absolute  lengths  gives  the  same  re- 
sults as  a  comparison  of  specific  amounts. 

The  average  regenerated  lengths  at  each  of  the  six  different  times 
will  be  taken  up  first.  At  two  days  the  average  regenerated  lengths 
for  the  first,  second  and  third  regenerations  are  respectively  0.22,  0.25 
and  0.26  mm.  At  four  days  the  corresponding  amounts  are  0.66,  0.75 
and  1.00.  At  six  days  they  are  1.36,  1.40  and  1.36,  but  the  low  value 
of  the  third  regeneration  is  due  to  a  single  exceptional  individual.  At 
eight  days  the  figures  are  2.18,  2.68  and  2.68.  At  ten  days  they  are 
3.55,  3.82  and  4.20  and  at  fourteen  days  5.34,  6.12  and  6.08.  In  all 
cases,  except  the  one  at  six  days  explained  above,  both  second  and  third 
regenerations  are  ahead  of  the  first.  Tlie  tliird  regeneration  is  greater 
than  the  second  at  two,  four  and  ten  days,  is  equal  to  the  second  at  eight 
days  and  less  than  the  second  at  six  and  fourteen  days.     Since  the  low 


47] 


RATE    OF    REGENERATION —ZELENY 


A7 


average  for  the  third  regeneration  at  six  days  is  due  to  a  single  excep- 
tional individual  it  is  more  proper  to  put  the  third  ahead  of  the  second 
at  this  time. 

A  comparison  of  the  three  regenerations  by  individual  cases  is 
shown  in  Table  32.  At  each  of  the  six  times  taken  the  number  of  cases 
showing  a  more  rapid  regeneration  is  greater  for  the  third  regeneration 
than  for  the  first  and  also  greater  for  the  second  than  for  the  first.  The 
third  is  ahead  of  the  second  at  two  times  (more  properly  three  times) 
and  equal  to  the  third  at  four  times  (more  properly  three). 

When  all  the  individual  cases  are  taken  together  both  third  and 
second  regenerations  are  again  distinctly  ahead  of  the  first  as  showni 
by  the  totals  in  Table  32.  The  third  is  ahead  of  the  second  in  twelve 
cases  (more  properly  thirteen)  and  the  second  ahead  of  the  first  in  eight 
cases  (more  properly  seven). 

Each  of  the  three  compai-isons  shows  that  both  second  and  third 
regenerations  are  more  rapid  than  first  regenerations.  The  third  regen- 
eration shows  a  slight  advantage  over  the  second  instance  in  all  three 
of  the  comparisons.  In  this  instance  the  difference  can  not  be  diie 
to  the  presence  of  newly  regenerated  cells  in  the  one  case  and  not  in  the 
other. 

TABLE  31 

Amblystoma  punctatum       Series  3967-3998 

Comparison  of  lengths  of  first,  second  and  third  regenerations 

Age  factor  eliminated 


Regener- 
ation   time 
in 
days 

Catalog 
number 

2 

3967 
3968 
3969 

Average 

4 

3970 
3971 
3972 
3973 

Average 

Regenerated  lengths  ir 

mm. 

First 
regeneration 

Second 
regeneration 

Third 
regeneration 

0.2 

0.25 

0.2 

0.25 

0.3 

0.2 

0.3 

0.27 
0.2 

0.22 

0.25 

0.26 

0.75 
0.7 
0.5 
0.7 

0.9 

0.75 
0.6 

1.0 

1.6 
0.8 
0.6 

0.66 

0.75 

1.00 

48 


ILLIXOIS    BIOLOGICAL    MONOGRAPHS 


148 


TABLE  31   (Continued) 

Amblystoma  punctatum       Series  3967-3998 

Comparison  of  lengths  of  first,  second  and  tliird  regenerations 

Age  factor  eliminated 


Regener- 

Regenerated lengths  in  mm. 

ation   time 

Catalog 

in 

number 

First 

Second 

Third 

days 

regeneration 

regeneration 

regeneration 

3974 

1.2 

1.2 



3975 

1.4 

1.5 

1.5 

3976 

1.3 

1.4 

1.6 

6 

3977 

1.5 

1.2 

0.6 

3978 

1.4 

1.7 

1.7 

Average 

1.36 

1.40 

1.36 

3980 

1.7 

2.4 

2.7 

3981 

1.9 

— 

2.9 

3982 

2.3 

2.6 

3.0 

8 

3984 

2.4 

2.8 

2.1 

3985 

2.6 

2.9 

2.7 

Average 

2.18 

2.68 

2.68 

3986 

4.1 

3.8 

4.7 

3987 

3.6 

3.7 

— 

3988 

3.5 

— 

3.9 

3989 

2.6 

3.9 

3.5 

10 

3990 

3.2 

4.25 

4.6 

3991 

4.3 

3.5 

4.35 

Average 

3.55 

3.82 

4.20 

3992 

5.5 

5.5 

5.7 

3993 

5.0 

5.75 

5.7 

3994 

— 

6.7 

6.9 

3995 

5.0 

5.7 

6.9 

14 

3997 

6.9 

6.7 

5.2 

3998 

4.3 

6.35 

— 

Average 

5.34 

6.12 

6.08 

49] 


RATE    OF    REGENERATION— ZELENY 


TABLE  32 


Amblystoma    punctatum       Series    3967-399S       Age    factor    eliminated 

Comparison  of  lengtlis  of  first,  second  and  third  regenerations 

Comparison  of  individual  cases 


Comparisons 


3rd  regen.  >  1st 
3rd  regen.  =  1st 
3rd   regen. <  1st 


2nd  regen.  >  1st 
2nd  regen.  =  1st 
2nd  regen.  <  1st 


3rd  regen.  >  2nd 
3rd  regen.  =  2nd 
3rd  regen.  <  2nd 


Two 
days 


Four 
days 


Six 

Eight 

days 

days 

3 

4 

0 

0 

1 

1 

3 

4 

1 

0 

1 

0 

1 

2 

2 

0 

1 

2 

Ten 
days 


Fourteen 
days 


Totals 

20 
1 

4 


ExPERiJiENT  IV      Amblystoma  punctatum       Series  3962-3999 

The  series  used  for  Experiment  III  furnishes  another  set  of  data 
for  the  effect  of  successive  removal.  When  the  third  operation  was  made 
the  removed  regenerated  tails  of  the  first  thirty  individuals  represented 
an  eleven-day  second  regeneration  and  those  of  the  second  thirty-indi- 
viduals an  eleven-day  first  regeueration.  A  direct  comparison  is  thus 
possible  between  the  first  and  the  second  regenerations.  It  is  not  possi- 
ble to  make  a  cut  exactly  at  the  border  line  between  old  and  new  tissue 
and  therefore  the  measurement  of  the  removed  regenerating  tail  is  not 
as  accurate  a  determination  as  is  the  direct  measurement  of  a  regener- 
ating unremoved  tail. 

The  data  are  shown  in  Table  33.  Twenty-five  individuals  are  avail- 
able for  each  regeneration.  The  average  of  the  first  regenerations  is 
4.55  =0.11  and  of  the  second  regenerations  4.50  -0.10.  The  first  regen- 
eration is  ahead  of  the  second  in  ten  cases,  the  second  is  ahead  of  the 
first  in  twelve  cases  and  three  cases  are  equal.  The  first  comparison 
shows  a  slight  difference  in  favor  of  the  first  regeneration  but  this  is 
so  much  less  than  the  probable  error  that  it  can  not  be  considered  as 
significant.  The  second  comparison  shows  a  slight  advantage  in  favor 
of  the  second  regeneration.  On  the  whole  the  data  indicate  essential 
equality  between  the  first  and  the  second  regenerations  at  eleven  days. 


50 


ILLIXOIS    BIOLOGICAL    MONOGRAPHS 

TABLE  33 

Amblystoma   punctatum       Series  3962-3999       Age  factor   eliminated 

Comparison   of   first  and   second   regenerations 

Eleven   days 


[50 


First 

Second 

First 

Second 

First 

Catalog 

regen. 

regen. 

ahead 

ahead 

and  second 

number 

mm. 

mm. 

of  second 

of  first 

equal 

3967 

4.0 

4.4 

0.4 

3968 

3.7 

3.5 

0.2 

3969 

4.9 

5.1 

0.2 

3970 

4.5 

4.7 

0.2 

3972 

4.7 

4.7 

* 

3973 

3.9 

4.3 

0.4 

3975 

4.5 

5.7 

1.2 

3976 

4.9 

4.9 

* 

3977 

3.8 

3.7 

0.1 

3978 

4.1 

4.5 

0.4 

3980 

4.9 

5.0 

0.1 

3981 

3.5 

4.4 

1.1 

3982 

5.0 

4.7 

0.3 

3984 

5.1 

4.0 

1.1 

3985 

5.8 

4.3 

1.5 

3986 

3.8 

4.1 

0.3 

3989 

4.8 

5.5 

0.7 

3990 

5.5 

4.3 

1.2 

3991 

4.1 

4.6 

0.5 

3992 

4.6 

4.1 

0.5 

3993 

4.5 

4.5 

* 

3994 

4.9 

5.0 

0.1 

3995 

4.5 

4.0 

0.5 

3997 

5.1 

4.2 

0.9 

3998 

4.8 

4.3 

0.5 

4.55±0.11 

4.50+0.10 

ten 
times 

twelve 
times 

three 
times 

Experiment  V  Amblystoma  punctatum  Series  6042-6100F 
This  series  was  devised  for  a  study  of  the  etfect  of  repeated  removal 
of  the  tail  upon  the  rate  of  metamorphosis.  The  removed  tails  were 
preserved  and  they  give  some  data  on  the  comparison  of  successive 
regenerations.  The  interest  of  the  results  lies  in  the  fact  that  the  suc- 
cessive regenerations  are  compared  within  single  individuals.  Thus  the 
effect  of  the  age  factor  is  not  eliminated.  Environmental  differences 
such  as  those  of  temperature  may  also  be  factors. 

The    eggs    were    hatched    on    March    25    to    29.    1915.     Approxi- 
matelv  one-half  in  length  of  the  tail  was  I'emoved  in  each  of  the  indi- 


51]  RATE    OF    REGENERATION— ZELENY  51 

viduals  ou  April  5.  The  new  tissue  was  removed  on  April  17  and 
again  ou  May  1,  May  10  and  May  19,  making  five  removals  in  all. 
The  second  removal  gives  the  fii-st  regeneration,  the  third  the  second, 
and  so  on.  The  regenerated  lengths  were  therefore  determined  by 
measurement  of  removed  parts.  This  does  not  give  as  accurate  a  deter- 
mination as  does  direct  measurement  without  removal  because  the  cut 
can  not  in  ordinary  practice  be  made  exactly  at  the  border  line  between 
old  and  new  tissue. 

The  data  are  given  in  Table  34.  The  first  regeneration  covers  a 
twelve-day  period,  the  second  fourteen  days  and  the  third  and  fourth 
each  nine  days. 

The  third  and  fourth  regenerations  are  the  only  ones  that  have  the 
same  time  interval.  Ten  individuals  are  available  for  this  comparison. 
The  average  for  the  third  regeneration  for  these  ten  is  1.30  mm.  and 
of  the  fourth  regeneration  1.17  mm.  When  all  individuals  are  taken 
without  regard  to  representation  of  both  regenerations  the  average  for 
the  third  regeneration  is  1.28  and  for  the  fourth  1.17.  In  seven  of  the 
ten  former  cases  the  third  is  ahead  of  the  fourth  regeneration,  in  two 
they  are  tied  and  in  one  the  fourth  is  ahead  of  the  third.  The  data 
therefore  show  an  advantage  of  the  third  over  the  fourth  regeneration. 

The  first  regeneration  ran  twelve  days  and  the  second  fourteen 
days.  The  maximum  rate  of  regeneration  comes  on  or  near  the  ninth 
day  and  the  rate  has  declined  to  a  low  point  by  the  fourteenth  day. 
However  it  is  not  possible  to  make  the  necessary  correction  because  of 
lack  of  data  on  the  rate  curve  for  this  particular  set  of  larvae.  Some 
facts  may  however  be  obtained  by  a  comparison.  Sixteen  individuals 
for  each  of  the  two  regenerations  are  available  for  comparison.  The 
average  for  the  first  regeneration  in  these  is  2.06  mm.  and  for  the  sec- 
ond 2.01  mm.  In  seven  the  first  is  ahead  of  the  second,  in  seven  the 
second  is  ahead  of  the  first,  and  two  are  tied.  When  all  individuals 
are  taken  without  regard  to  representation  of  both  regenerations  the 
average  for  the  first  regeneration  is  1.99  -0.03  mm.  for  a  twelve-day 
period  and  for  the  second  regeneration  2.01  for  a  foiirteen-day  period. 
The  difference  between  the  two  values  is  not  significant,  but  when  the 
longer  time  interval  taken  by  the  second  regeneration  is  considered  the 
conclusion  is  reached  that  the  first  regeneration  is  more  rapid  than  the 
second. 

The  data  thus  indicate  a  progressive  decrease  in  rate  from  the 
first  to  the  fourtli  regenerations.  This  result  taken  in  connection  with 
the  results  obtained  from  the  experiments  in  which  the  age  factor  is 
eliminated  makes  it  highly  probable  that  the  decrease  in  rate  of  regen- 
eration observed  here  is  due  to  increase  in  age  and  not  to  the  effect  of 
successive  removal. 


52 


ILLINOIS    BIOLOGICAL    MOXOGRAPHS 


Amblystoma  punctatum       Series  6042-6100  F      Age  factor  eliminated 
Successive  regenerations  in  single  individuals 


First 

Second 

Third 

Fourth 

regeneration 

regeneration 

regeneration 

regeneration 

Catalog 

mm. 

mm. 

mm. 

mm. 

number 

Twelve 

Fourteen 

Nine 

Nine 

days 

days 

days 

days 

6042 

2.0 

2.4 

1.6 

6043 

1.8 

2.5 

1.5 

1.4 

6044 

2.2 

6046 

2.2 

2.2 

1.3 

1.3 

6047 

2.2 

2.1 

1.4 

1.3 

6048 

2.0 

2,2 

6049 

2.3 

1.8 

1.5 

1.0 

6050 

1.8 

6052 

2.0 

6053 

1.9 

6055 

1.9 

6056 

1.7 

6057 

2.0 

6058 

2.0 

6059 

1.9 

6061 

1.5 

6062 

2.3 

6065 

1.5 

6067 

1.6 

6068 

1.6 

6071 

2.0 

6072 

1.9 

6076 

2.1 

6077 

2.0 

6079 

2.0 

6080 

1.8 

6081 

1.9 

6082 

1.9 

2.0 

1.0 

1.1 

6083 

2.0 

2.1 

1.3 

1.1 

6084 

1.9 

6085 

2.0 

2.0 

1.5 

1.5 

6086 

2.2 

6087 

1.8 

1.0 

0.8 

6088 

2.1 

2.4 

1.4 

1.2 

6090 

2.5 

6093 

2.3- 

2.2 

1.0 

O.S 

6094 

2.1 

53] 


RATE    OF    REGENERATION— ZELESY 
TABLE  34   (Continued) 


53 


First 

Second 

Tliird 

Fourth 

regeneration 

regeneration 

regeneration 

regeneration 

Catalog 

mm. 

ram. 

mm. 

mm. 

number 

Twelve 

Fourteen 

Nine 

Nine 

days 

days 

days 

days 

6096 

2.1 

6097 

2.5 

1.6 

6098 

1.8 

2.1 

6099 

2.2 

6100D 

2.0 

6100E 

1.8 

1.6 

6100F 

2.2 

2.0 

1.1 

1.0 

Average 

1.99±0.03 

2.01 

1.28 

1.17 

Rate  per  day 

0.166 

0.144 

0.142 

0.130 

Experiment  VI       Bufo  americ.vnus      Series  6283-6323 

This  series  was  designed  for  the  study  of  the  effect  of  successive 
removal  of  the  tail  upon  the  rate  of  metamorphosis.  The  lengths  of 
the  removed  regenerating  tails  however  are  of  some  value  in  a  com- 
parison of  successive  regenerations  though  here  as  in  Experiment  V 
age  and  external  factors  are  not  eliminated. 

The  eggs  were  laid  on  April  20-21,  1915.  The  tadpoles  were  col- 
lected on  April  27  and  the  first  removals  were  made  on  April  28. 
The  first  metamorphosis  was  completed  on  June  11.  Tlie  average 
total  length  at  the  time  of  the  first  removal  was  10.9  mm.  and  the 
average  tail  length  6.4  mm.  The  average  removed  length  was  3.8  mm., 
which  is  approximately  60  per  cent  of  the  tail  length.  Tlie  second 
removal  was  made  on  May  7  and  gives  a  nine-day  period  for  tlie  first 
regeneration.  The  third  removal  of  May  17  gives  a  ten-day  period 
for  the  second  regeneration.  The  fourth  removal  on  May  26  gives  a 
nine-day  period  for  the  third  regeneration.  As  in  the  case  of  Experi- 
ment V  the  cuts  could  not  in  practice  be  made  to  come  exactly  at  the 
border  line  between  old  and  new  tissue  and  the  accuracy  of  the  meas- 
urements is  therefore  not  as  great  as  in  those  cases  in  which  the 
lengths  were  taken  directly  from  the  animal  without  removal  of  the  tail. 

The  data  are  shown  in  Table  35.  The  first,  second  and  third  re- 
generation lengths  are  given  for  sixty  individuals.  The  first  and  third 
regenerations  have  the  same  time  interval  and  are  therefore  directly 
comparable.     The  average  for  the  first  regeneration  is  1.94  "0.02  mm. 


54 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


IS4 


and  for  the  third  1.80  '0.03  mm.,  a  difference  in  favor  of  the  first  re- 
generation of  0.14  *0.05  mm.  This  represents  a  regeneration  of  0.51  mm. 
per  unit  of  removed  length  in  the  first  regeneration  and  0.47  mm.  per 
unit  in  the  third  regeneration.  A  comparison  of  individual  cases  shows 
that  the  first  regeneration  is  ahead  of  the  third  in  36  individuals,  the 
third  is  ahead  of  the  first  in  IS  individuals  and  5  are  tied.  The  differ- 
ence between  the  two  regenerations  is  thiis  probablj'  significant.  As  in 
Experiment  V  the  decrease  is  probably  due  to  the  age  factor. 

The  second  regeneration  has  a  time  interval  of  ten  days,  one  day 
more  than  the  first  and  third  regenerations.  In  the  absence  of  know- 
ledge concerning  the  rate  curve  for  toad  tadpoles  of  this  age  no  cor- 
rection can  be  applied.  The  rates  per  day  for  the  three  regenerations 
are  however  given  in  the  table. 


TABLE  35 
Bufo  americanus       Series   6283-6323       Age  factor  not  eliminated 
Successive  regenerations  of  tail 


First 

Second 

Third 

Catalog 

regeneration 

regeneration 

regeneration 

number 

Nine  days 

Ten  days 

Nine  days 

Length  in  mm. 

Length  in  mm. 

Length  in  mm. 

6283  a 

2.1 

2.0 

1.9 

b 

1.5 

2.1 

1.6 

c 

1.7 

2.1 

1.7 

6285   a 

2.3 

1.9 

2.0 

b 

2.3 

2.1 

2.0 

c 

2.0 

2.4 

2.4 

6287   a 

1.9 

2.1 

2.1 

b 

2.1 

2.0 

1.9 

c 

1.8 

2.3 

1.8 

6289   a 

1.9 

2,3 

2.2 

b 

2.1 

2.0 

1.7 

c 

2.2 

2.1 

2.0 

6291   a 

2.1 

2.2 

2.0 

b 

1.9 

1.9 

1.8 

c 

2.0 

1.9 

1.4 

6295  a 

2.0 

-'.0 

2.U 

b 

2.1 

2.1 

1.8 

c 

1.8 

1.9 

1.9 

6297  a 

1.9 

2.0 

2.0 

b 

1.9 

2.1 

1.8 

0 

1.9 

2.0 

1.8 

6299  a 

1.8 

2.0 

1.5 

b 

2.0 

2.0 

1.7 

55] 


RATE    OF    REGENERATION— ZELENY 
TABLE  35    (Continued) 


First 

Second 

Third 

Catalog 

regeneration 

regeneration 

regeneration 

number 

Nine  days 

Ten  days 

Nine  days 

Length  in  mm. 

Length  in  mm. 

Length  in  mm. 

c 

1.8 

1.9 

1.3 

6301   a 

2.0 

1.5 

1.4 

b 

l.S 

1.9 

1.2 

c 

1.7 

1.8 

1.4 

6303   a 

1.9 

1.9 

1.3 

b 

1.9 

1.9 

1.5 

c 

1.8 

2.0 

1.6 

6305  a 

1.9 

2.0 

1.5 

b 

1.7 

1.8 

2.0 

c 

2.1 

2.2 

1.9 

6307  a 

2.1 

1.8 

2.0 

b 

1.9 

2.0 

2.1 

c 

l.S 

1.9 

1.8 

6309  a 

2.0 

1.9 

1.9 

b 

1.9 

1.9 

2.0 

c 

2.0 

2.0 

1.7 

6311  a 

1.7 

2.4 

1.8 

b. 

1.8 

1.9 

2.1 

c 

2.0 

2.1 

2.0 

6313  a 

2.0 

2.3 

1.7 

b 

l.S 

1.7 

2.0 

c 

1.7 

1.7 

1.5 

6315  a 

1.9 

2.4 

2.0 

b 

2.0 

2.1 

1.6 

c 

1.9 

1.9 

6317  a 

1.9 

2.0 

1.3 

b 

l.S 

2.2 

2.0 

c 

1.9 

2.1 

1.8 

6319  a 

2.2 

2.0 

2.0 

b 

2.1 

2.0 

2.0 

c 

1.9 

1.9 

2.0 

6321  a 

2.3 

2.0 

l.S 

b 

1.7 

2.0 

1.9 

c 

2.0 

2.3 

1.3 

6323   a 

2.1 

2.1 

1.7 

b 

1.8 

2.3 

2.0 

c 

1.9 

2.2 

2.0 

Average 

1.94±0.02 

2.02=0.02 

1.80±0.03 

Rate  per  day 

0.216 

0.202 

0.200 

56 


ILLINOIS    BIOLOGICAL    MOXOGRAPHS 


[56 


Experiment' VII  Rana  clamitans  Series  3557-3624 
This  experiment  deals  with  the  relative  completeness  of  regenera- 
tion after  successive  removals  within  single  individuals.  Age  and  ex- 
ternal factors  are  not  eliminated.  A  more  complete  description  of  the 
experiment  is  given  under  "Completeness  of  Regeneration."  The  tail 
length  averaged  approximately  17.0  mm.  About  one-half  of  the  tail 
was  removed  at  the  first  operation.  At  succeeding  operations  the  cut 
came  as  near  as  possible  to  the  border  line  between  old  and  new  tissue. 
The  first  removals  came  on  October  23,  1911,  the  second  on  November 
28,  the  third  January  3,  the  fourth  February  9,  the  fifth  March  16  and 
the  sixth  April  4.  At  the  time  of  the  last  removal  the  hind  legs  were 
just  starting  to  grow. 

The  data  are  given  in  Table  36.  Tlie  first  regeneration  interval  is 
36  days,  the  second  36,  the  third  37,  the  fourth  36  and  the  fifth  39 
days.  Each  one  of  these  is  more  than  sufficient  for  the  completion  of 
the  regenerative  process.  The  individuals  are  divided  into  three  sets, 
A,  B,  and  C.  A,  with  seven  individuals,  has  no  record  for  the  first  regen- 
eration ;  the  second  regeneration  is  9.8  mm.,  the  third  9.3,  the  fourth 
8.5  and  the  fifth  8.6.  B,  also  with  seven  individuals,  has  no  record  for 
the  first  regeneration ;  the  second  is  9.1  mm.,  the  third  8.9,  the  fourth 
7.2  and  the  fifth  7.8.  C,  with  nineteen  individuals,  has  a  first  regen- 
eration average  of  8.6  mm.,  a  second  of  8.0,  a  third  of  7.5,  a  fourth  of 
5.5  and  a  fiftli  of  6.4.  In  all  the  cases  there  is  a  decrease  in  the  amount 
regenerated  with  successive  removal  except  for  the  fifth  regeneration, 
which  has  in  each  case  an  increase  over  the  fourth.    It  is  probable  that 

TABLE  36 

Rana  clamitans       Series  3564-3624       Age  factor  not  eliminated 

Completed  successive  regenerations  compared 


First 

Second 

Third 

Fourth 

Fifth 

Catalog 

Number  of 

regenera- 

regenera- 

regenera- 

regenera- 

regenera- 

Set 

number 

individ- 

tion 

tion 

tion 

tion 

tion 

uals 

36   Days 

36   Days 

37   Days 

36   Days 

39  Days 

3564 

A 

to 
3570 

7 

9.8 

9.3 

8.5 

8.6 

3578 

B 

to 
3584 

7 

9.1 

8.9 

7.2 

7.8 

3586 

C 

to 
3624 

19 

8.6 

8.0 

7.5 

5.5 

6.4 

57]  RATE    OF    REGESERATION—ZELEXY  57 

the  decrease  is  due  to  increase  iu  age.  The  increase  from  the  fourth  ta 
the  fifth  regeneration  may  be  due  to  some  special  characteristic  of  the 
stage  immediately  preceding  metamorphosis  or  it  may  merely  indicate 
the  existence  of  some  uncontrolled  external  factor  such  as  food  or 
temperature. 

Discussion' 

The  evidence  shows  clearly  that  wlieii  the  age  factor  is  eliminated 
there  is  no  decrease  in  rate  of  regeneration  with  successive  removal. 
On  the  contrary  the  second  regeneration  is  more  rapid  than  the  first 
up  to  the  period  of  maximum  rate.  The  second  regeneration  however 
passes  its  maximum  sooner  than  does  the  first  and  after  the  tenth  day 
the  latter  therefore  catches  up  to  the  former  in  total  amount  regener- 
ated. There  is  no  striking  difi'erence  between  the  second  and  the  third 
regenerations  but  in  each  comparison  the  third  has  a  slight  advantage. 

When  the  successive  regenerations  in  single  individuals  are  com- 
pared, the  rate  decreases  with  successive  removal.  This  decrease  is 
undoubtedly  due  to  the  age  factor. 

The  possibility  has  suggested  itself  that  the  second  regeneration 
starts  out  at  a  more  rapid  rate  than  the  first  because  the  cells  at  the 
cut  surface  were  undergoing  regenerative  changes  at  the  time  of  the 
new  operation  and  can  therefore  start  the  process  much  faster  than 
can  the  old  cells  at  the  first  surface  of  regeneration.  Following  a  first 
removal  there  is  a  considerable  degree  of  reorganization  of  the  cells 
at  the  cut  surface,  accompanied  by  active  migration.  During  this 
period,  which  in  Rana  clamitans  lasts  two  or  three  days,  there  is  little 
or  no  mitotic  cell  division.  Then  follows  a  division  period  which 
reaches  its  maximum  at  seven  to  ten  daj's.  Its  decline  is  associated 
with  the  oncoming  of  tissue  differentiation  (Sutherland  1915,  iletealf 
1915). 

A  special  study  has  been  made  of  tlie  ivlative  rates  of  second 
regenerations  from  old  cells  following  a  cut  inside  of  the  first  removal 
level  and  from  new  cells  following  a  cut  outside  of  the  first  level.  Tliis 
comparison  shows  only  a  very  slight  difference  in  favor  of  tlie  new 
cells  and  this  is  largely  confined  to  the  early  stages,  the  period  of  cell 
migration. 

The  i)eriod  of  increase  in  rate  is  the  period  of  active  cell  iiiultipH- 
cation  and  the  decline  in  rate  is  associated  with  cell  differentiation. 
The  second  regeneration  tlierefore  reaches  the  period  of  differentiation 
slightly  in  advance  of  the  first  regeneration. 

Apart  from  the  slowing  due  to  age  there  is  no  indication  of  a 
limitation  of  the  amount  of  new  material  that  may  be  produced  by 
regeneration.     The  actual  limitation  comes  not  from  the  using  up  of 


58  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [58 

regenerative  or  developmental  energy  or  of  determiners  by  repeated 
regeneration  but  from  changes  in  the  non-regenerating  part  associated 
with  age.  In  another  place  there  is  a  discussion  of  the  possibility  that 
there  may  be  an  eft'ect  upon  the  rate  of  developmental  processes  in 
the  organism  as  a  whole  due  to  continued  regeneration  of  a  part.  This 
is  studied  particularly  in  connection  with  the  effect  of  regeneration 
upon  rate  of  metamorphosis  in  Amphibia. 

Regeneration  studies  in  general  and  those  on  successive  regener- 
ation in  particular  make  it  improbable  that  there  is  a  definite  number 
of  cell  generations  between  the  fertilized  egg  and  the  end  product,  the 
differentiated  cells.  The  possibilit}'  that  certain  cells  may  remain  in 
an  early  cell  generation  can  not  be  wholl.y  excluded  as  an  explanation 
of  at  least  a  part  of  first  regeneration  phenomena.  Under  suitable  stimu- 
lation such  cells  may  be  postvilated  to  take  up  development  where  it 
had  left  off.  The  definite  descriptions  of  de-differentiations  of  cells 
as  well  as  other  facts  of  regeneration  argue  against  this  conclusion. 
The  view  that  there  can  be  no  such  definite  immber  of  cell  generations 
is  strengthened  by  the  facts  of  .successive  regeneration.  It  does  not 
seem  probable  that  embryonic  cells  of  an  early  cell  generation  can  be 
held  in  reserve  through  repeated  regenerations. 

The  explanation  of  regeneration  by  the  theory  of  duplicate  sets  of 
determiners  meets  difficulties  in  undimini.shed  successive  regenerations. 
The  greater  the  number  of  repeated  regenerations  the  greater  the  diffi- 
culties of  explanation  on  this  basis.  Of  course  the  difficulty  does  not 
hold  for  the  hypothesis  that  everj'  cell  or  nearly  every  cell  contains  a 
full  set  of  determiners. 

The  earlier  appearance  of  the  maximum  rate  in  the  second  than 
in  the  first  regeneration  may  be  due  to  the  more  rapid  progress  of  the 
cells  in  the  early  cell  migration  period  alone  or  it  may  be  due  to  the 
acceleration  of  the  whole  developmental  cycle. 

Summary 

1.  The  age  factor  was  eliminated  in  Experiments  I  to  IV.  Ex- 
periments I  and  II  deal  with  tadpoles  of  Rana  clamitans  and  Experi- 
ments III  and  IV  with  larvae  of  Amblystoma  punetatum. 

2.  In  Experiment  I  approximately  one-half  of  the  tail  was  re- 
moved. At  six  days  tlie  average  first  regeneration  length  is  2.01  mm. 
and  the  average  second  regeneration  length  2.18  mm.  In  five  eases  the 
first  exceeds  tlie  second  and  in  six  tlie  second  exceeds  the  first.  The 
corresponding  specific  lengths  are  0.194  and  0.205.  The  first  regen- 
eration exceeds  the  second  in  two  sets,  the  second  exceeds  the  first  in 
eight  and  one  is  tied.  The  second  regeneration  has  the  advantage  in  all 
the  comparisons. 


59]  RATE    OF    REGEXERATIOX—ZELENY  59 

3.  At  eight  days  in  Experiment  I  the  average  first  regeueration 
length  is  3.06  mm.,  and  the  second  3.42  mm.  The  fii'st  exceeds  the  sec- 
ond in  three  sets  and  the  second  exceeds  the  first  in  seven.  The  corre- 
sponding average  specific  lengths  are  0.298  and  0.323.  In  four  sets 
the  first  regeneration  exceeds  the  second  and  in  six  the  second  exceeds 
the  first.  The  second  regeneration  has  the  advantage  in  all  the  com- 
parisons. 

4.  The  advantage  of  the  second  regeneration  over  the  first  in 
Experiment  I  holds  true  of  second  regenerations  from  both  old  tissue 
and  new  tissue  levels. 

5.  In  Experiment  II  observations  were  made  at  the  1/10,  1/3,  1/2 
and  2/3  levels  in  a  sufficient  number  of  individuals  to  yield  valid  data. 
Regeneration  measurements  were  made  at  each  of  these  levels  4,  6,  8, 
10,  1214,  18  and  56  days  after  the  operations.  The  second  regen- 
eration at  aU  of  them  tends  to  be  ahead  of  the  first  until  the  tenth  day, 
after  which  the  first  regeneration  catches  up.  The  maximum  rate  for 
both  regenerations  is  reached  before  this  time  and  earlier  for  the  second 
than  for  the  first  regeneration. 

6.  In  Experiment  III  two-thirds  of  the  tail  was  removed.  A 
comparison  of  the  first,  second  and  third  regenerations  was  made  at 
2,  4,  6,  8,  10  and  14  days..  At  two  days  the  first,  .second  and  third 
regenerations  average  respectively  0.22,  0.25  and  0.26  mm.  The  cor- 
responding values  at  four  days  are  0.66,  0.75  and  1.00;  at  six  days 
1.36,  1.40  and  1.46 ;  at  eight  days  2.18,  2.68  and  2.68 ;  at  ten  days  3.55, 
3.82  and  4.20;  at  fourteen  days  5.34,  6.12  and  6.08.  The  advantage  is 
in  favor  of  the  second  and  third  regenerations  as  opposed  to  the  first 
and  of  the  third  as  opposed  to  the  second.  Individual  comparisons  at 
each  of  the  different  times  as  well  as  in  the  experiment  as  a  whole 
show  the  same  results. 

7.  The  removed  tails  in  the  preliminary  procedure  of  Experi- 
ment III  furnish  the  data  of  Experiment  IV  and  allow  a  comparison 
of  the  first  and  second  regenerations  at  eleven  days.  The  procedure  is 
however  subject  to  greater  error  than  that  of  Experiments  I  to  III. 
Twenty-five  individuals  for  each  regeneration  give  an  average  of  4.55 
-0.11  mm.  for  the  first  regeneration  and  4.50  -0.10  mm.  for  the  second 
regeneration.  The  first  regeneration  is  ahead  of  the  second  in  ten 
cases,  the  second  ahead  of  the  first  in  twelve  eases  and  three  are  equal. 
The  two  regenerations  must  be  considered  as  essentially  equal. 

8.  In  Experiments  V  and  VI  the  age  factor  is  not  eliminated. 
Successive  regenerations  in  single  individuals  are  compared.  In  Ex- 
periment V  one-half  of  the  tail  in  Arably stoma  larvae  was  removed. 
In  Experiment  VI  60  per  cent  of  the  tail  of  toad  tadpoles  was  removed. 


60  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [60 

The  time  intervals  vary  somewhat  in  each  set  but  it  is  evident  in  botli 
cases  that  there  is  a  decrease  in  rate  of  regeneration  from  the  first  to 
the  third  and  fourth  regenerations.  This  decrease  is  undoubtedly  due 
to  increase  in  age  and  not  to  successive  removal. 

9.  In  Experiment  VII  a  comparison  of  the  completeness  of  re- 
generation in  single  individuals  of  Rana  clamitans  shows  a  progressive 
decrease  in  amount  regenerated  from  the  first  to  the  fourth  regener- 
ation and  an  increase  from  the  fourth  to  the  fifth.  In  this  experiment 
also  the  age  factor  is  not  eliminated  and  the  decrease  is  probably  due 
to  increase  in  age. 


61]  RATE    OF    REGESERATIOS  —  ZELESY 


PART  III 

THE  EFFECT  OF  LEVEL  OP  THE  CUT  UPON  THE  RATE  AND 
COMPLETENESS  OF  REGENERATION 

The  present  study  gives  a  description  of  some  experiments  made  to 
define  more  accurately  than  has  been  done  the  exact  relation  between 
the  level  of  the  cut  and  rate  of  regeneration  and  especially  the  relation 
of  this  factor  to  the  other  factors  affecting  rate  and  completeness  of 
regeneration.  The  factor  is  one  of  great  interest  because  if  it  is  true  that 
the  ratio  between  length  regenerated  per  unit  time  and  length  removed 
is  a  constant  it  follows  that  no  matter  how  much  material  is  removed 
regeneration  is  always  completed  in  the  same  time.  It  is  therefore  of 
great  interest  to  determine  the  extent  to  which  this  statement  is  true, 
to  analyze  the  elements  of  the  level  factor  and  to  determine  its  relation 
to  other  factors. 

ExPERiiiENT  I  Rax.v  clamitans  Series  3676-3765 
The  tadpoles  were  collected  on  December  9,  1911,  and  first  removals 
were  made  in  two-thirds  of  the  individuals  on  December  22.  A  second 
removal  was  made  in  these  individuals  on  January  8,  and  at  the  same 
time  a  first  removal  in  the  other  one-third.  Measurements  were  made 
four,  six,  eight,  ten,  twelve  and  a  half,  eighteen  and  fifty-six  days  after 
the  operations  of  Januarj-  8.  The  first  and  second  regenerations  are 
treated  separately  and  the  second  regenei'ations  are  taken  up  first  because 
they  have  a  larger  number  of  individuals  and  therefore  give  the  more 
uniform  results. 

Second  Regenerations 

The  different  amounts  removed  approximate  6,  10,  IS,  31,  49  and  67 
per  cent  of  the  tail  length.  There  are  four  individuals  at  the  lowest 
removal,  averaging  1.5  mm.,  seven  at  the  next,  averaging  2.8  mm.,  five 
at  the  third  with  an  average  of  4.9  mm.,  ten  at  the  fourth  with  8.4  mm., 
eight  at  the  fifth  with  13.1  mm.,  and  ten  at  the  sixth  M'ith  18.1  mm.  The 
data  are  given  in  tables  37  to  40  and  in  graphic  form  in  figures  4  to  17. 

The  regenerated  lengths  at  ten  daj-s  will  be  taken  iip  first  because 
at  this  time  the  period  of  maximum  rate  has  been  passed  and  its  full 
effect  is  represented.    Differentiation  of  the  tissues  has  begun  but  there 


62  ILLINOIS    BIOLOGICAL    MONOGRAPHS  [62 

is  still  a  considerable  prodiiction  of  new  cells  by  mitotic  division  except  in 
the  individuals  with  the  two  shortest  removals  in  which  the  process  is 
completed.  The  regenerated  lengths  for  the  six  levels  beginning  witli  the 
shortest  removal  are  respectively  1.0,  1.3,  1.4,  2.3,  3.7  and  5.1  mm.  The 
data  are  given  in  the  last  two  columns  of  table  37.  There  is  very  dis- 
tinctly an  increase  in  regenerated  length  with  increase  in  removed 
length.  Dividing  the  regenerated  length  by  the  removed  length  at  each 
level,  the  fractions  obtained  are 


1.0 

1.3 

1.4 

2.3 

3.7 

5.1 

T5' 

Ys 

1^9' 

'SA 

131' 

isl' 

which  give  the  specific  regenerated  lengths  or  lengths  regenerated  per 
unit  of  removed  lengths.  These  values  are  0.67,  0.46,  0.29,  0.28,  0.28  and 
0.28.  They  show  a  remarkable  constancy  for  removed  lengths  of  4.9 
mm.  and  over.  The  relations  between  removed  lengths  and  regenerated 
lengths  are  further  shown  in  figure  4  which  gives  the  removed  lengths 
along  the  horizontal  axis  and  the  regenerated  lengths  parallel  to  the 
vertical  axis.  The  plotted  line  of  correlation  between  the  two  values 
is  straight  except  for  the  two  lowest  removed  lengths.  The  specific 
lengths  are  given  in  Figure  5  in  which  the  removal  lengths  again  are 
along  the  horizontal  axis  and  the  lengths  regenerated  per  unit  of  removed 
length  parallel  to  the  vertical  axis.  The  line  of  correlation  is  straight 
and  parallel  to  the  horizontal  axis  for  the  four  highest  removals.  For 
these  therefore  the  regenerated  length  is  directly  proportional  to  the 
removed  length  or  in  other  words  within  these  limits  the  same  percent- 
age of  the  removed  length  is  regenerated  in  each  within  the  given  time 
of  ten  days. 

The  two  lowest  removed  lengths  give  a  higher  specific  rate  than  the 
others.  They  regenerate  a  higher  percentage  of  the  removed  length 
within  the  given  time. 

The  ten  day  period  is  chosen  as  the  fii'st  example  because  it  is  the 
first  one  to  receive  the  full  benefit  of  the  periods  of  maximum  rate  of 
regeneration,  the  periods  during  which  rapid  multiplication  of  cells 
takes  place.  The  other  periods  give  results  which  agree  in  general 
features  after  the  first  few  days  with  those  at  ten  daj's  but  depart  from 
them  in  certain  respects. 

The  remaining  periods  will  now  be  taken  up  in  turn  beginning  with 
the  shortest. 

During  the  first  four  days  after  the  operation  the  rate  of  regenera- 
tion is  slow,  the  new  tissue  being  derived  largely  from  migration  of 
ceUs  over  the  cut  surface.  Measurements  of  regeneration  at  this  time 
are  especially  subject  to  error  because  of  the  small  amount  regenerated 


63] 


RATE    OF    REGENERATION— ZELEKY 


63 


and  because  of  irre^ilarity  in  the  outer  edge  of  the  regenerating  tissue. 
The  regenerated  lengths  at  four  days  are  respectively  0.22,  0.39,  0.24, 
0.42,  0.50  and  0.52  mm.    These  data  are  given  in  table  37  and  are  rep- 


mm. 
5.0 


1.5    2.8  4.9  8.4  13.1 

— >-      Lengths  removed  in  mm. 
Figure  4  Rana  clamitans    Second  regenerations     Ten  days 


18.1 


mm. 
0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


1.5 


13.1 


18.1 


Figure  5 


2.8         4.9  8.4 

— >■      Lengths  removed  in  mm. 
Raiia  clamitans    Second  regenerations     Specific  lengths     Ten  days 

resented  graphically  in  figure  6.     Dividing  the  regenerated  lengths  by 
the  removed  lengths  the  fractions  obtained  are 
0.22         0.39         0.24        0.42        0.50 


0.52 

islb 

0.04  and  0.03.     These 
There  is  on  the  wliole 


1.50  2.80  4.90  8.40  13.10 
giving  specifie  lengths  of  0.15,  0.14,  0.05,  0.05, 
relations  are  represented  graphically  in  figure  7. 
a  slight  increase  in  regenerated  length  with  increase  in  removed  length 
but  this  increase  is  not  proportional  to  the  amount  removed  so  that  the 
proportion  regenerated  decreases  with  increase  in  removed  length.    The 


64 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[64 


approach  to  equality  in  regeneration  at  this  time  is  probably  due  to 
the  fact  that  the  new  tissue  is  largely  made  up  of  migrating  cells  and 
there  is  not  a  striking  difference  in  the  extent  of  the  migration  at  the 
different  levels. 

The  specific  length  of  material  regenerated  after  the  smallest 
removals  is  greater  than  that  regenerated  after  the  larger  removals  not 
only  at  four  days  but  also  later.  It  is  probable  that  the  factors  involved 
during  the  first  few  days  of  regeneration  are  quite  different  from  those 
during  later  days.  Following  the  injury  there  is  a  disintegration  of 
injured  cells  associated  with  an  active  migration  of  the  epidermal  cells 


Figure  6 


1.5    2.8         4.9  8.4  13.1 

— >-      Lengths  removed  in  mm. 
Rana  clamitans      Second  regenerations     Four  days 


mm. 
0.20 
0.10 


o,  Figure  7 


1.5    2.8  4.9  8.4 

— >-      Lengths  removed  in  mm. 
Ram  clamitans    Second  regenerations 


Specific  lengths     Four  days 


over  the  cut  surface.  There  is  practically  no  mitotic  cell  division.  The 
rapid  multiplication  of  cells  comes  later.  These  processes  of  cell  migra- 
tion apparently  are  not  essentially  different  at  the  different  levels.  They 
are  local  responses  of  the  cells  at  the  cut  surface.  With  the  appearance 
of  rapid  cell  multiplication  there  is  a  marked  difference  at  different 
levels  though  the  shortest  removals  still  show  a  greater  specific  length 
than  the  others  probably  because  in  their  case  the  migrated  cells  make 
up  a  large  percent  of  the  total  material  of  the  new  part. 

Between  the  end  of  the  fourth  and  the  end  of  the  sixth  day  after 
the  operation  mitotic  cell  division  becomes  very  rapid  and  the  rate  of 
regeneration  for  second  regenerations  reaches  its  maximum  at  a  majority 
of  the  levels  on  the  sixth  day.  At  six  days  the  regeneration  for  the  six 
levels  is  respectively  0.62,  0.80,  0.70,  1.1,  1.7  and  2.3  mm.,  as  shown  in 


65] 


RATE    OF    REGENERATION —ZELENY 


65 


Table  37.  A  graphic  representation  is  given  in  Figure  8.  There  is  a  grad- 
ual increase  with  increase  in  removed  length.  The  fractions  obtained  by 
dividing  by  the  removed  lengths  are : 

"^0.62        0.80        0.70         1.1         1.7  2.3 


1.5  2.8  4.9  8.4      13.1  18.1 

They  give  specific  lengths  of  0.42,  0.30,  0.14,  0.13,  0.13  and  0.13.  The 
smaller  removals  still  have  the  larger  specific  lengths  but  with  removals 
of  4.9  mm.  and  more  there  is  an  approach  to  constancy.  The  relations 
are  shown  graphically  in  Figure  9. 


1.5    2.8  4.9  8.4  13.1 

— >■      Lengths  removed  in  mm. 
Figure  8       Rana  clamitans    Second  regenerations     Six  days 


0.40 
0.30 
0.20 
0.10 


Figure  9 


1.5    2.8         4.9  8.4 

— >      Lengths  removed  in  mm. 
Ram  clamitans     Second  regenerations 


13.1 


Specific  lengths     Six  days 


The  rate  of  regeneration  between  the  sixth  and  the  eighth  day  for 
second  regenerations  is  not  quite  as  high  as  for  the  preceding  period, 
but  mitotic  divisions  are  still  very  numerous  and  dift'erentiation  of  the 
cells  is  just  beginning.  At  eight  days  the  regenerated  lengths  are 
respectively  0.9,  1.1,  1.2,  1.8,  2.7  and  3.7  mm.  as  shown  in  table  37. 
The  increase  in  regeneration  with  increase  in  removed  length  is  evident. 
The  relations  are  shown  in  Figure  10.  Dividing  by  tlie  removed  lengths 
the  fractions  obtained  are 

0.9         1.1         1.2         1.8        2.7  3.7 


1.5 


2.8 


4.9 


8.4       13.1 


18.1 


66 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[66 


giving  the  specific  regenerations  0.60,  0.39,  0.24,  0.22,  0.21,  0.20.  There 
is  a  graphic  representation  in  Figiire  11.  As  before,  the  two  shortest 
removals  give  the  highest  specific  rates  but  beyond  these  there  is  an 
approach  to  constancy  though  there  is  still  a  slight  decrease  with  increase 
in  removal. 

The  ten  day  values  have  already  been  given. 

Between  ten  and  twelve  and  a  half  days  after  the  operation  there 
is  j]o  further  growth  in  the  case  of  the  two  shortest  removals.  In  the 
two  medium  removals  the  process  is  completed  at  twelve  and  a  half 
days.     In  the  two  longest  removals  there  is  still  a  small  amount  of 


mm. 
4.0 


Figure  10 


1.5    2.8  4.9  8.4  13.1 

— >      Lengths  removed  in  mm. 
Ram  dantitans    Second  regenerations    Eight  days 


18.1 


mm. 
0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


Figure  11 


13.1 


18.1 


1.5    2.8         4.9  8.4 

— >-      Lengths  removed  in  mm. 

Rana  clamitans  Second  regenerations    Specific  lengths    Eight  days 

proliferation  after  this  time.  At  twelve  and  a  half  days  the  regenerated 
lengths  are  1.0,  1.3,  1.6,  2.6,  4.4  and  6.2  mm.  as  shown  in  Table  38.  The 
increase  with  increase  in  removed  length  is  continuous.     This  is  shown 


67]  - 


RATE    OF    REGEKERATION—ZELENY 


67 


in  graphic   form  in   figure   12. 
fractions  obtained  are 

1.0        1.3         1.6 


Dividing  by  tlie  removed  lengths  the 


2.6         4.4  6.2 

1.5       'Yi        4.9       ~SA       m        '"         181 
giving  specific  lengths  of  0.67,  0.46,  0.33,   0.31,  0.34  and   0.34 


graph  for  specific  lengths  is  shown  in  figure  13. 
mm. 
6.0 


The 
There  is  still  a  fair 


Figure  12 

•o      ™™- 
£,     0.70 

fe     0.60 

I     0.50 

<~     0.40 

0.30 

0.20 

0.10 


ti 


1.5    2.8  4.9  8.4 

— >-      Lengths  removed  in  mm. 

Rana  damitans      Second  regenerations 


Twelve  and  a  half  days 


Figure  13 


1.5    2.8  4.9  8.4 

— >-      Lengths  removed  in  mm. 
Rana  damiians    Second  regenerations 


13.1  18.1 

Specific  lengths       Twelve 


and  a  half  days 


apin-oach  to  constancy  with  removals  of  4.9  mm.  and  above.  The  rela- 
tive increase  in  the  case  of  the  higher  removals  is  due  to  the  fact  that 
regeneration  is  continuing  in  them  after  it  has  stopped  in  the  others. 


68 


ILLINOIS    BIOLOGICAL    MOXOGRAPHS 


168 


Therefore  the  data  after  this  time  are  values  for  the  completeness  of 
I'egeneration  rather  than  for  the  rate. 

Between  twelve  and  a  half  and  eighteen  days  after  tlie  operation 
there  is  no  further  regeneration  in  the  tails  with  the  four  shortest  re- 
movals. Two  of  them  even  exhibit  a  decrease  in  size.  The  two  longest 
removals  show  only  a  slight  increase.  At  eighteen  days  the  regenerated 
lengths  are  respectively  1.0,  1.2,  1.5,  2.6,  4.8  and  7.0  mm.  as  given  in 
Table  38.  The  same  data  are  represented  in  graphic  form  in  Figure  14. 
Dividing  by  the  removed  lengths  the  fractions  obtained  are 
1.0        1.2         1.5        2.6        4.8  7.0 


1.5        2.8        4.9         8.4       13.1  18.1 

giving  specific  lengths  of  0.67,  0.43,  0.31,  0.31,  0.37  and  0.39.  Tlie  graph  is 
shown  in  Figure  15. 


mm. 
7.0 


3.0 


Figure  14 


1.5    2.8         4.9  8.4 

— >      Lengths  removed  in  mm. 
Ram  clainitans       Second   regenerations 


Eighteen  days 


At  eighteen  days  there  is  very  little  regeneration  at  any  of  the 
levels  and  at  some  of  them,  especially  the  shorter  removals,  a  consider- 
able absorption  of  regenerated  material.  Regeneration  may  therefore 
be  considered  as  completed  at  this  time.  However  the  measurements  for 
56  days  are  given  in  order  to  show  the  changes.  The  regenerated 
lengths  at  that  time  are  0.9,  0.7,  1.6,  2.5,  5.2  and  7.1   mm.     These  data 


69] 


mm. 

0.70 
0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


Figure  15 


RATE    OF    REGENERATION— ZELEXY 


1.5    2.8  4.9  8.4 

— >■      Lengths  removed  in  mm. 
Ra)ia  ciainitans     Second  regenerations 


Specific  lengths      Eight- 


een days 


are  given  in  table  38  and  are  represented  in  grajiliie  form  in  figiire  16. 
Dividing  by  the  average  removed  lengths,  which  differ  somewhat  from 
the  previous  ones  because  of  the  death  of  certain  individuals,  the  frac- 
tions obtained  are 

0.9        0.7         1.6        2.5        5.2  7.1 

T5'       'ZG       1^       ~82      iZ2        '"        17^ 


mm. 

7.0 


1.5    2.6  4.9  S.2 

— y      Lengths  removed  in  mm. 
Ram  ciainitans       Second  regenerations 


Fifty-six  days 


70 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[70 


giving  specific  regenerations  of  0.60,  0.27,  0.33,  0.31,  0.39  and  0.40.  Tliese 
are  shown  in  the  graph  given  in  figure  17.  Because  of  the  absorption 
of  regenerated  tissue  in  the  shorter  removals  and  a  slight  growth  in  the 
longer  ones  the  latter  show  a  comparative  increase  in  specific  lengths. 


0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


Figure  17 


1.5        2.6  4.9  8.2 

— >-      Lengths  removed  in  mm. 
Ram  clainitans      Second  regenerations 


Specific  lengths      Fifty- 


six  days 


For  a  comparison  of  completeness  of  regeneration  it  is  better  to 
take  the  greatest  lengths  regenerated  at  each  level  rather  than  the 
amounts  regenerated  at  any  particular  time  because  the  shorter  levels 
complete  regeneration  and  begin  to  absorb  the  tissues  sooner  than  do 
the  longer  ones.  On  this  basis  the  greatest  regenerated  lengths  at  each 
of  the  six  levels  are,  for  the  1.5  mm.  level  1.0  mm.  reached  at  ten  days, 
for  the  2.8  level  1.3  mm.  reached  at  ten  days,  for  the  4.9  level  1.6  mm. 
reached  at  twelve  and  a  half  days,  for  the  8.4  level  2.6  mm.  reached  at 
twelve  and  a  half  days,  for  the  13.2  level  5.2  mm.  reached  at  fifty-six 
days,  and  for  the  17.9  level  7.1  mm.  reached  at  fifty-six  days.  These 
data  are  given  in  tables  37,  38,  39  and  40  and  in  gr.iphic  form  in  figure 
18.  At  the  last  two  levels  there  was  a  slight  increase  from  eighteen 
to  fift.y-six  days  but  this  almost  certainly  came  during  the  early  part 
of  the  period  and  the  values  are  therefore  completed  values.  Dividing 
by  the  removed  lengths  the  fractions  obtained  are 


1.0 

1.3 

1.6 

2.6 

5.2 

and 

7.1 

1.5 

2.8 

4.9 

8.4 

13.2 

17.9 

giving  specific  lengths  of  0.67,  0.46,  0.33,  0.31,  0.39  and  0.40.  The  graph 
is  given  in  Figure  19.  The  high  values  for  the  two  short  levels  are 
probably  due  to  the  fact  that  the  cells  migrating  to  the  cut  surface  form 


RATE    OF    REGEXERATIOX  —  ZELENY 


mm. 
7.0 

6.0 


J      2.0 


Fig 

ure  18 

•a 

mm. 

0.70 

c 

0.60 

be 

0.50 

« 

0.40 

to 

0.30 

0) 

0.20 

o 

0.10 

Figure  19 

ness 


1.5    2.8  4.9  8.4  13.2 

— >-      Lengths  removed  iu  mm. 
Rana  dainitans    Second  regenerations     Completeness 


17.9 


1.5    2.8 


13.2 


4.9  8.4 

• — >      Lengths  removed  in  mm. 
RiDUi  dainitans    Second  regenerations     Specific  lengths 


17.9 

Complete- 


a  large  proportion  of  the  total  mass  of  the  regenerated  organ.  Since 
apparentlj'  the  lengtli  of  this  mass  of  cells  is  very  much  alike  at  all 
levels  as  indicated  by  the  facts  of  the  four  day  regenerations,  the  speeitic 
lengths  for  these  short  removals  are  greater  than  for  the  others.  The 
high  values  of  the  two  longest  removals  are  due  to  a  continuation  of 


72 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[72 


regeneration  at  these  levels  after  it  has  ceased  at  the  others.  At  ten 
days  the  specific  lengths  regenerated  are  very  nearly  the  same  at  all  the 
levels  except  the  first  two. 


Rana  clamitans 


TABLE  37 
Series  3676-3765 


Second  regenerations 


Catalog 
number 

Removeo 
length 

4    Days 

6   Days 

8  Days 

10 

Days 

Percent 
removed 
Average 

Regen- 
erated 
length 

Specific 
lengtli 

Regen- 
erated 

length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

3676 

1.3 

0.27 

0.60 

0.9 

1.0 

3682 

1.6 

0.18 

0.60 

0.9 

1.0 

3730 

1.6 

0.39 

0.75 

0.9 

0.9 

6 

3754 

1.6 

0.06 

O.G.", 

0.9 

1.1 

Average 

1.5 

0.22 

0.15 

0.62 

0.42 

0.9 

0.60 

1.0 

0.67 

3677 

2.0 

0.30 

0.6 

0.9 

0.9 

3696 

2.1 

0.48 

0.8 

1.0 

1.1 

3701 

3.2 

0.42 

0.8 

1.1 

1.2 

3713 

2.8 

0.36 

0.8 

0.9 

0.9 

10 

3719 

3.1 

0.30 

0.8 

1.1 

1.4 

3749 

2.8 

0.48 

0.6 

1.2 

1.4 

3750 

3.5 

0.42 

1.3 

1.7 

1.9 

Average 

2.8 

0.39 

0.14 

0.80 

0.30 

1.1 

0.39 

1.3 

0.46 

3678 

5.0 

0.20 

0.5 

0.9 

1.0 

3684 

5.5 

0.15 

0.7 

1.2 

1.4 

3702 

4.7 

0.42 

0.8 

1.1 

1.3 

18 

3720 

4.6 

0.06 

0.3 

1.3 

1.8 

3756 

4.8 

0.36 
0.24 

1.0 

0.14 

1.3 
1.2 

0.24 

1.7 

Average 

4.9 

0.05 

0.70 

1.4 

0.29 

' 

' 

73] 


RATE    OF    REGEXERATION—ZELENY 


73 


Rana  clamitans 


TABLE  37  (Continued) 
Series  3676-3765  Second  regenerations 


Catalog 
number 

Removed 
lengtli 

4   Days 

6    Days          1 

8  Days 

10  Days 

Percent 
removed 

Average 

Regen- 
ciated 
length 

Specil'.c 
lengtli 

Regen- 
erated 
length 

.Specific 
length 

Regcn 
erated 
length 

.Specific 
length 

Regen- 
erated 
length 

Specific 
length 

3679 

8.4 

0.30 

0.7 

1.4 

1.9 

3685 

9.3 

0.60 

1.2 

1.9 

2.3 

3697 

7.3 

0.48 

1.2 

1.7 

2.2 

3703 

9.3 

0.45 

1.3 

2.0 

2.5 

3715 

7.9 

0.24 

0.9 

1.7 

2.3 

31 

3721 

8.7 

0.57 

1.3 

1.9 

2.3 

3733 

8.5 

0.36 

1.0 

1.9 

2.4 

3739 

9.6 

0,36 

1.0 

1.8 

2.4 

3751 

6.7 

0.45 

1.1 

1.7 

2.1 

3757 

8.0 

0.42 

1.2 

2.1 

2.8 

Average 

8.4 

0.42 

0.05 

1.1 

0.13 

1.8 

.  0.22 

2.3 

0.28 

3686 

14.5 

0.60 

2.1 

3.4 

4.8 

3698 

14.9 

0.50 

1.5 

3.3 

4.3 

3704 

14.0 

0.45 

2.2 

3.3 

4.4 

3716 

12.7 

0.39 

1.7 

2.4 

3.4 

3722 

12.5 

0.60 

1.6 

2.6 

3.6 

49 

3740 

13.9 

0.30 

1.1 

2.1 

3.0 

3752 

11.2 

0.54 

1.7 

2.5 

3.4 

3758 

11.0 

0.60 

1.5 

2.2 

2.9 

Average 

13.1 

0.50 

0.04 

1.7 

0.13 

2.7 

0.21 

3.7 

0.28 

3680 

16.0 

0.60 

1.9 

3.0 

4.2 

3681 

21.2 

0.84 

3.0 

4.0 

5.6 

3687 

19.7 

0.54 

3.6 

5.6 

6.0 

3699 

21.0 

0.54 

2.2 

4.3 

5.9 

3705 

17.6 

0.72 

2.0 

3.6 

4.8 

3717 

17.6 

0.42 

2.6 

3.6 

5.2 

67 

3723 

18.4 

0.30 

2.3 

3.7 

5.3 

3735 

16.5 

0.48 

2.0 

3.4 

5.5 

3741 

16.0 

0.30 

1.9 

3.0 

5.4 

3753 

16.8 

0.42 

2.0 

2.5 

3.8 

Average 

18.1 

0.52 

0.03 

2.3 

0.13 

3.7 

0.20 

5.1 

0.28 

74 


ILLIXOIS    BIOLOGICAL    MONOGRAPHS 


[74 


Rana  clamitans 


TABLE  38 
Series  3676-3765 


Second   regenerations 


Catalog 
number 

Kemoved 
length 

1.3 

12J 

Days 

18 

Days 

56  Days 

Highest  values 

Percent 
removed 
Average 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

3676 

1.0 

1.0 

0.7 

1.0 

3682 

1.6 

1.0 

1.0 

1.1 

1.1 

3730 

1.6 

0.9 

0.9 

0.7 

0.9 

6 

3754 

1.6 

1.2 

1.2 

1.1 

1.2 

Average 

1.5 

1.0 

0.67 

1.0 

0.67 

0.9 

0.60 

1.0 

0.67 

3677 

2.0 

0.9 

0.9 

0.7 

0.9 

3696 

2.1 

1.0 

1.0 

0.7 

1.1 

3701 

3.2 

0.9 

0.9 

0.5 

1.2 

3713 

2.8 

1.4 

1.3 

1.4 

10 

3719 
3749 
3750 

3.1 

2.8 
3.5 

1.4 
2.0 
1.3 

1.3 

2.0 
1.3 

0.9 

1.4 
2.0 
1.9 

Average 

2.8 

1.3 

0.46 

1.2 

0.43 

0.7 

0.27 

1.3 

0.46 

3678 

5.0 

1.1 

1.1 

1.1 

3684 

5.5 

1.4 

1.5 

1.4 

1.5 

3702 

4.7 

1.3 

1.3 

1.3 

1.3 

18 

3720 

4.6 

2.3 

1.9 

2.0 

2.3 

3756 

4.8 

1.8 

1.6 

1.6 

1.8 
1.6 

Average 

4.9 

1.6 

0.33 

1.5 

0.31 

0.33 

0.33 

3679 

8.4 

1.9 

2.1 

2.1 

3685 

9.3 

2.8 

3.0 

2.6 

3.0 

3697 

7.3 

2.4 

2.3 

2.1 

2.4 

3703 

9.3 

2.6 

2.5 

2.5 

2.5 

3715 

7.9 

2.6 

2.6 

2.8 

2.8 

3721 

8.7 

2.6 

2.3 

2.2 

2.6 

31 

3733 
3739 

8.5 
9.6 

2.6 
3.0 

2.6 
2.9 

2.8 

2.8 
3.0 

3751 

6.7 

2.4 

2.5 

2.3 

2.5 

3757 

8.0 

3.1 

3.2 

3.1 

3.2 

Average 

8.4 

2.6 

0.31 

2.6 

0.31 

2.5 

0.31 

2.6 

0.31 

75] 


RATE    OF    REGENERATION— ZELENY 
TABLE  38  (Continued) 


75 


Catalog 
number 

Removed 
length 

12i 

Regen- 
erated 
length 

Days 

Specific 
length 

18 

Days 

56  Days 

Highest  values 

Percent 
removed 
Average 

Regen- 
erated 
length 

Specific 
length 

Regen. 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

3686 

14.5 

5.3 

5.2 

5.3 

3698 

14.9 

5.0 

5.4 

5.4 

5.4 

3704 

14.5 

5.2 

5.5 

5.4 

5.5 

3716 

12.7 

4.2 

5.1 

4.4 

5.1 

3722 

12.5 

3.9 

3.5 

4.2 

4.2 

49 

3740 
3752 

13.9 
11.2 

4.6 
4.1 

5.6 
4.0 

6.8 

6.8 
4.1 

3758 

11.0 

3.6 

4.1 

4.9 

4.9 

Average 

13.1 

4.4 

0.34 

4.8 

0.37 

5.2 

0.39 

5.2 

0.39 

3680 

16.0 

5.2 

6.4 

6.6 

6.6 

3681 

21.2 

6.3 

7.3 

7.2 

7.3 

3687 

19.7 

6.6 

7.0 

7.0 

3699 

21.0 

7.1 

7.5 

7.2 

7.5 

3705 

17.6 

6.4 

6.2 

6.0 

6.4 

67 

3717 

17.6 

6.0 

6.7 

6.4 

6.7 

3723 

18.4 

6.5 

8.1 

8.3 

8.3 

3735 

16.5 

6.5 

7.8 

8.0 

8.0 

3741 

16.0 

5.8 

6.9 

7.0 

7.0 

3753 

16.8 

5.2 

6.4 

7.1 
7.1 

7.1 
7.1 

Average 

18.1 

6.2 

0.34 

7.0 

0.39 

0.40 

0.40 

TABLE  39 

Rana  clamitans       Series  3676-3765       Summary       Second  regenerations 

Lengths  regenerated  at  different  levels  at  different  times 


Percent    of 

tail  length 

removed 

Length 
removed 
In  mm. 

Number 
of  indi- 
viduals 

Days  after  operation 

4 

6 

8 

10 

12/2 

18 

56 

6 

1.5 

4 

0.22 

0.6 

0.9 

1.0 

1.0 

1.0 

0.9 

10 

2.8 

7 

0.39 

0.8 

1.1 

1.3 

1.3 

1.2 

0.7 

18 

4.9 

5 

0.24 

0.7 

1.2 

1.4 

1.6 

1.5 

1.6 

31 

8.4 

10 

0.42 

1.1 

1.8 

2.3 

2.6 

2.6 

2.5 

49 

13.1 

8 

0.50 

1.7 

2.7 

3.7 

4.4 

4.8 

5.2 

67 

1«.1 

10 

0.52 

2.3 

3.7 

5.1 

6.2 

7.0 

7.1 

76 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[76 


TABLE  40 

Rana  clamitans       Series  3676-3765       Summary       Second  regenerations 

Lengtlis  regenerated  at  different  levels  at  different  times 


Percent   of 

tail  length 

removed 

Length 
removed 
in  mm. 

Number 
of  indi- 
viduals 

Days  after  operation 

4 

6 

8 

10 

12/2 

18 

56 

6 

1.5 

4 

0.15 

0.42 

0.60 

0.67 

0.67 

0.67 

0.60 

10 

2.8 

7 

0.14 

0.30 

0.39 

0.46 

0.46 

0.43 

0.27 

18 

4.9 

5 

0.05 

0.14 

0.24 

0.29 

0.33 
0.31 

0.31 

0.33 

31 

8.4 

10 

0.05 

0.13 

0.22 

0.28 

0.31 

0.31 

49 

13.1 

8 

0.04 

0.13 

0.21 

0.28 

0.34 

0.37 

0.39 

67 

18.1 

10 

0.03 

0.13 

0.20 

0.28 

0.34 

0.39 

0.40 

First  Kegenerations 

The  data  for  first  regenerations  are  from  a  different  set  of  indi- 
viduals than  those  for  second  regenerations.  The  two  kinds  of  opera- 
tions were  made  on  the  same  day.  The  general  results  obtained  from  the 
first  regenerations  are  in  full  agreement  with  those  obtained  from  the 
second  regenerations  but  there  is  greater  variability  because  of  the 
smaller  number  of  individuals.  The  average  per  cents  of  the  tail  length 
removed  are  respectively  6,  10,  17,  30,  48  and  62  for  the  six  levels. 
The  first  of  these  has  two  individuals  averaging  1.5  mm.  of  removed 
tail,  the  second  five  individuals  with  an  average  of  2.6  mm.,  the  third 
three  individuals  with  an  average  of  4.6,  the  fourth  eight  witli  an  average 
of  8.2,  the  fifth  five  with  an  average  of  13.0  and  the  sixth  five  with  an 
average  of  16.7.  The  data  for  these  experiments  are  given  in  Tables 
41,  42,  43  and  44  and  in  Figures  20  to  35. 

The  progress  of  a  first  regeneration  is  similar  to  that  of  a  second 
except  that  the  maximum  is  reached  later  in  the  case  of  first  regenera- 
tions. In  the  present  series  the  maximum  specific  rate  for  first  regenera- 
tions comes  between  the  sixth  and  the  eighth  day  after  the  operation. 
A  comparison  of  the  two  regenerations  is  made  in  the  section  on  the 
effect  of  siaccessive  removal.  The  change  in  rate  during  the  process  of 
regeneration  is  also  discussed  in  a  separate  section. 


m 


RATE    OF    REGEXERATIOX—ZELEXY 


77 


The  lengths  regenerated  during  the  first  four  days  are  respectively 
0.27.  0.15,  0.51,  0.45,  0.46  and  0.51  for  the  six  levels.  There  is  no 
regular  increase  with  removed  length.  The  data  are  given  in  Table  41 
and  in  Figure  20.  The  specific  lengths  regenerated  are  0.17,  0.06,  0.11, 
0.05,  0.03  and  0.03.  They  are  shown  in  Table  41  and  in  Figure  21.  As  in 
tlie  case  of  the  second  regeneration  the  shortest  removals  have  the 
largest  proportional  amounts.    This  first  period  being  the  period  of  cell 


1.5 


13.0 


1^ 
Figure  20 


;.6        4.6  8.2 

— >-      Lengths  removed  in  mm. 
Rana  claiiiilans    First  regenerations     Four  days 


16.7 


migration  with  very  little  cell  division  it  is  probable  that  the  length  of 
the  material  furnished  in  this  way,  as  measured  along  the  main  axis  of 
the  individual,  is  independent  of  the  level  of  the  cut.  The  area  of  the  cut 
surface  of  course  is  greater  at  the  more  proximal  than  at  the  more  distal 
levels  so  that  the  actual  total  mass  of  regenerated  material  is  greater  at 
the  deeper  levels. 

At  six  days  the  rate  of  first  regenerations  is  rapidly  increasing, 
the  maximiim  rate  coming  between  six  and  eight  days.  The  lengths 
regenerated  at  six  days  are  respectively  0.47,  0.5, 1.0, 1.1,  1.6  and  1.6  mm. 


mm. 
0.20 
0.10 


1.5 


13.0 


Figure  21 


2.6         4.6  8.2 

— >-      Lengths  removed  in  mm. 
RaiM  damitans       First  regenerations     Specific  lengths 


16.7 


Four  days 


78 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[78 


They  are  shown  in  Table  41  and  in  Figiire  22.  There  is  in  general  an 
increase  with  increase  in  removed  lengtli  but  the  first  is  not  proportional 
to  the  second.  The  specific  lengths  are  0.30,  0.18,  0.22,  0.13,  0.12  and 
0.09  as  shown  in  Table  41  and  Figure  23.  The  shorter  removals  still  have 
proportionately  the  greater  regenerations. 

■g     mm. 

rt      2.0 


1.5    2.6         4.6  S.2  i; 

— >      Lengths  removed  in  mm. 
Figure  22      Rana  claiiiitans.      First  regenerations 


Si.x  days 


0.30 
0.20 
0.10 


•5  Figure  23 


1.5    2.6         4,6  8.2 

— >-      Lengths  removed  in  mm. 
Rana  damitans       First  regenerations 


Specific  lengths      Six  days 


The  maximum  rate  of  regeneration  is  reached  between  the  sixth 
and  the  eighth  day.  The  regenerated  lengths  at  eight  days  are  0.8,  0.7, 
1.5,  1.7,  2.6  and  3.0  mm.  The  data  are  shown  in  Table  41  and  Figure  24. 
With  one  exception  there  is  increase  in  regenerated  length  with  increase 
in  removed  length.  The  specific  regenerated  lengths  are  0.53,  0.27,  0.33, 
0.21,  0.20  and  0.18  as  shown  in  Table  41  and  Figure  25.  The  shortest 
removals  have  the  greatest  specific  regenerations  but  at  8.2  mm.  and 
above  there  is  an  approach  to  constancy. 


79] 


RATE    OF    REGENERATION— ZELENY 


79 


Figure  24 


1.5 


13.0 


2.6        4.6  8.2 

— >-      Lengths  removed  in  mm. 
Rana  daiiiitans      First  regenerations     Eight  days 


M 


0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


1.5 


13.0 


2.6        4.6  8.2 

— >-      Lengths  removed  in  mm. 
Figure  26  Ra)i-i  claiiiilans         First  regenerations     Specific  lengths     Eight  days 


Between  the  eighth  and  the  tenth  day  there  is  a  rapid  decrease  in 
rate  associated  with  tissue  differentiation.  The  regenerated  lengths  at 
ten  days  are  0.9,  1.0,  1.7,  2.3,  3.8  and  4.5  mm.  as  show^l  in  Tal)l(>  41 
and  Figure  26.  There  is  an  uninterrupted  increase  in  regeneration  with 
increase  in  removed  length.  The  specific  lengtlis  are  0.58,  G.3b.  0.37, 
0.28,  0.29  and  0.27  as  shown  in  Table  41  and  Figure  27. 


80 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[80 


Between  teu  and  twelve  and  a  half  days  regeneration  is  slow,  reach- 
ing its  end  for  the  two  shortest  removals  at  the  latter  day.  The  regen- 
erated lengths  at  twelve  and  a  half  days  are  0.9,  1.2,  1.8,  2.6,  4.7  and 


mm. 

5.0 


1.5    2.6        4.6  8.2  13.0 

— >■      Lengths  removed  in  mm. 
Figure  26       Rana  damitans.   First  regenerations     Ten  days 


mm. 

0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


1.5    2.6        4.6  8.2 

— >-      Lengtlis  removed  in  mm. 
Rana  damitans       First  regenerations 


Specific  lengtlis      Ten  days 


5.8  mm.  as  shown  in  Table  42  and  Figure  28.  There  is  a  steady  increase 
with  increase  in  removed  length.  The  specific  lengths  are  0.61,  0.46, 
0.39,  0.31,  0.36  and  0.35  as  shown  in  Table  42  and  Figure  29.  There  is 
an  approach  to  constancy  in  the  four  largest  removals. 


811 


RATE    OF    REGENERATION —ZELENY 


81 


Between  twelve  and  a  half  and  eighteen  days  the  regenerated 
material  is  decreasing  in  the  case  of  the  two  shortest  removals,  has  made 
no  progress  in  the  third  and  in  tlie  three  longest  removals  the  increase  is 
very  sliglit.  The  data  therefore  are  of  value  more  particularly  in  con- 
nection with  the  problem  of  the  relative  completeness  of  regeneration 
from  the  different  levels.    The  regenerated  lengths  at  eighteen  days  are 


mm. 
6.0 


13.0 


16.7 


1.5    2.6         4.6  8.2 

— >-      Lengths  removed  in  mm. 
Figure  28       Rana  damitans      First  regenerations       Twelve  and  a  lialf  days 


„ 

mm 

01 

0,70 

C3 

0.60 

13 

0.50 

u 

0.40 

ji 

0.30 

hfi 

a 

0.20 

13.0 


16.7 


1.5    2.6        4.6  8.2 

— >■      Lengths  removed  in  mm. 
Figure  29      Rana  claiiiitaits      First  regenerations     Specific  lengths     Twelve  and 
a  half  days 


82 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


182 


0.9,  1.1,  1.8,  2.7,  5.5  and  6.8  mm.  as  shown  in  Table  42  and  Figure  30. 
There  is  a  regular  increase  with  increase  iu  removed  length.  The 
specific  lengths  are  0.60,  0.42,  0.39,  0.33,  0.42  and  0.40  as  shown  in 
Table  42  and  Figure  31.  Though  there  are  irregularities  the  specific 
lengths  approach  constancy  at  all  levels  except  the  most  distal  one. 
Between  eighteen  and  fifty-six  days  there  is  practically  no  increase 


mm. 
7.0 


4.0 
3.0 


1.0 


1.5    2.6        4.6  8.2 

— >■      Lengths  removed  in  mm. 
Figure  30     '  Rana  dainiians.     First  regenerations 


Eighteen  days 


mm. 

0.70 
0.60 
0..50 
0.40 
0.30 
0.20 
0.10 


Figure  31.       Ran 
days 


1..5    2.6  4.6  8.2  13.0 

— y      Lengths  removed  in  mm. 
'  daiiiitans       First  regenerations      Specific  lengths 


83] 


RATE    OF    REGENERATION— ZELENY 


83 


in  regenerated  length  and  some  absorption  of  material  especially  ^vith 
the  shorter  removals.  The  regenerated  lengths  at  fifty-six  days  are  0.7, 
1.1,  1.5,  2.5,  5.5  and  6.9  mm.  as  shown  in  Table  42  and  Figure  32.  There 
is  a  regular  increase  in  regeneration  from  the  shortest  to  the  longest 
removal.  The  specific  lengths  are  0.45,  0.42,  0.34,  0.30,  0.42  and  0.41 
as  shown  in  Table  42  and  Figure  33.  These  data  are  of  value  only  for 
mm. 

7.0 


Figure  32 

•a 

mm. 

c 

0.50 

<D 

0.40 

.a 

M 
C 

0.30 
0.20 

0.10 

Fig 


1.5    2.6        4.6  8.2  13.0 

— >•      Lengths  removed  In  mm. 

Ram  clamitans    First  regenerations     Fifty-six  days 


13.0 


16.7 


1.5    2.6         4.6  8.2 

— >      Lengths  removed  in  mm. 
ure  33     Rami  damitans    First  regenerations    Specific  lengths    Fifty-six  days 


84 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[84 


a  comparison  of  completeness  of  regeneration  but  for  such  a  comparison 
it  is  better  in  some  ways  to  compare  the  regenerations  at  the  time  when 
absorption  lias  not  begun.  The  greatest  average  regenerated  length 
attained  for  the  1.5  mm.  level  is  0.9  mm.  at  ten  days,  for  the  2.6  level 
1.2  at  twelve  and  a  half  days,  for  the  4.6  level  1.8  at  twelve  and  a  half 
days,  for  the  8.2  level  2.7  at  eighteen  days,  for  the  13.0  level  5.5  at 
eighteen  days  and  for  the  16.7  level  6.9  at  fifty-six  days.  There  is  an  ■ 
uninterrupted  increase  from  the  shortest  to  the  longest  removal  in  com- 
plete amount  regenerated.    This  is  shown  graphically  in  Figure  34.   The 


7.0 


Figure  34 

-a 

mm. 

0.70 

<s 

0.60 

0.50 

a 
S, 

0.40 
0.30 
0.20 

o 
<a 

0.10 

1.5    2.6         4.6  8.2  13.0 

— >-      Lengths  removed  in  mm. 
Rana  dainitans      First  regenerations     Completeness 


Figure  35 


5    2.6         4.6  8.2 

— >-      Lengths  removed  in  mm. 
Rana  clamitans       First  regenerations 
Completeness 


Specific  lengths 


85] 


RATE    OF    REGENERATION— ZELENY 


85 


completed  regenerations  are  less  than  the  removed  lengths.  The  specific 
completed  regenerated  lengths  obtained  as  before  by  dividing  by  the 
removed  lengths  are  0.61,  0.46,  0.39,  0.33,  0.42  and  0.41,  as  shown  in 
table  42  and  figure  35.  The  greater  specific  lengths  from  the  shortest 
removals  are  probablj'  due  as  in  the  case  of  the  second  regenerations 
to  the  fact  that  a  greater  proportion  of  their  substance  is  made  up  of 
cells  that  have  migrated  over  the  cut  surface  during  the  first  stages  of 
regeneration.  This  migrated  material  is  not  essentially  different  in  axial 
length  at  the  diiferent  levels.  The  largest  removals  have  a  greater  spe- 
cific length  than  the  medium  ones  because  regeneration  continues  at  the 
former  levels  after  it  has  ceased  at  the  latter. 

On  the  whole  there  is  no  essential  difference  between  the  results 
obtained  from  first  regenerations  and  those  obtained  from  second  regen- 
erations. The  latter  give  the  more  regular  data  because  the  averages  are 
taken  from  a  larger  number  of  individuals. 


Rana  clamitans 


TABLE  41 
Series  3676-3765 


First  regenerations 


Catalog 
number 

Removed 
length 

4  I 

Regen- 
erated 
length 

)ays 

Specific 
length 

6   Days 

8  Days 

10 

Regen- 
erated 
length 

Days 

Percent 
removed 
Average 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

Specific 
length 

3706 

1.4 

0.24 

0.54 

0.9 

1.0 

6 

3742 

1.7 

0.30 

0.40 

0.7 

0.8 

Average 

1.5 

0.27 

0.17 

0.47 

0.30 

0.8 

0.53 

0.9 

0.58 

3688 

2.5 

0.12 

0.3 

0.3 

0.7 

3707 

3.2 

0.24 

0.8 

1.1 

1.4 

3724 

2.6 

0.06 

0.5 

0.8 

1.1 

10 

3743 

2.5 

0.03 

0.1 

0.4 

0.8 

3760 

3.1 

0.30 

0.6 

0.9 

1.1 

Average 

2.6 

0.15 

0.06 

0.5 

0.18 

0.7 

0.27 

1.0 

0.38 

86 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[86 


87] 


RATE    OF    REGEXERATIOX —ZELENY 


87 


Rana  clamitans 


TABLE  42 
Series  3676-3765 


First  regenerations 


Catalog 
number 

Re- 
moved 
length 
in  mm. 

12*  Days 

18 

Days 

56  Days 

Percent 
removed 
Average 

Regen- 
erated 
length 
mm. 

Specific 
length 

Regen- 
erated 
length 

Specific 
length 

Regen- 
erated 
length 
mm. 

Specific 
length 

3706 

1.4 

1.0 

0.9 

0.7 

6 

3742 

1.7 

0.9 

0.9 

0.7 

Average 

1.5 

0.9 

0.61 

0.9 

0.60 

0.7 

0.45 

3688 

2.5 

0.9 

0.9 

0.7 

3707 

3.2 

1.4 

1.3 

0.7 

3724 

2.6 

1.4 

1.4 

1.2 

10 

3743 

2.5 

1.0 

1.0 

1.7 

3760 

3.1 

1.2 

1.1 

1.1 

Average 

2.6 

1.2 

0.46 

1.1 

0.42 

1.1 

0.42 

3708 

5.3 

2.3 

2.3 

1.8 

3726 

4.3 

1.4 

1.4 

1.4 

17 

3762 

4.1 

1.7 

1.8 

1.4 

Average 

4.6 

1.8 

0.39 

1.8 

0.39 

1.5 

0.34 

3690 

9.7 

2.6 

2.7 

2.2 

3709 

8.8 

3.2 

3.4 

3.3 

3727 

8.3 

2.2 

2.2 

2.2 

3745 

10.0 

4.4 

4.8 

4.2 

3744 

6.0 

1.8 

1.7 

30 

3761 
3763 

6.6 
8.5 

2.2 
2.9 

2.3 
3.1 

1.8 

3689 

6.3 

1.6 

1.7 

1.4 

Average 

8.2 

2.6 

0.31 

2.7 

0.33 

2.5 

0.30 

3710 

12.3 

3.9 

3.9 

3.9 

3728 

12.8 

4.8 

5.4 

5.8 

3746 

13.3 

5.7 

7.0 

6.8 

48 

3764 

14.6 

5.3 

6.8 

6.5 

3765 

12.2 

3.9 

4.5 

4.5 

Average 

13.0 

4.7 

0.36 

5.5 

0.42 

5.5 

0.42 

3692 

16.8 

4.3 

5.0 

5.2 

3693 

17.2 

6.5 

7.3 

6.6 

3711 

17.0 

7.0 

7.7 

8.3 

62 

3729 

16.1 

5.5 

6.7 

6.4 

3749 

16.2 

5.6 

7.1 

7.8 
6.9 

Average 

16.7 

5.8 

0.35 

6.8 

0.40 

0.41 

ILLJXOIS    BIOLOGICAL    MOXOCRAPHS 

TABLE  43 

Rana    clamitans       Series    3676-3765       Sumniaiy       First    regenerations 

Lengths  regenerated  at  different  levels  at  different  times 


Percent  of 

tail   length 

removed 

Length 

removed 

in  mm. 

Number 
of  indi- 
viduals 

Days  after  operation 

4 

6 

8 

10 

12/2 

18 

56 

6 

1.5 

2 

0.27 
0.15 

0.5 
0.5 

1.0 

0.8 

0.9 

0.9 

0.9 

0.7 

10 

2.6 

5 

0.7 

1.0 

1.2 

1.1 

1.1 

17 

4.6 

3 

0.51 

1.5 

1.7 

1.8 

1.8 

1.5 

30 

8.2 

8 

0.45 

1.1 

1.7 
2.6 

2.3 

2.6 

2.7 

2.5 

48 

13.0 

5 

0.46 

1.6 

3.8 

4.7 

5.5 

5.5 

62 

16.7 

5 

0.51 

1.6 

3.0 

4.5 

5.8 

6.8 

6.9 

TABLE  44 

Rana    clamitans       Series    3676-3765       Summary       First    regenerations 

Specific  lengths  regenerated  at  different  levels  at  different  times 


Percent  of 

tail   length 

removed 

Length 

removed 

in  mm. 

Number 
of  indi- 
viduals 

Days  after  operation 

4 

6 

8 

10 

12/2 

18 

56 

6 

1.5 

2 

0.17 

0.30 

0.53 

0.58 

0.61 

0.60 

0.45 

10 

2.6 

5 

0.06 

0.18 

0.27 

0.38 

0.46 

0.42 

0.42 

17 

4.6 

3 

0.11 

0.22 

0.33 

0.37 

0.39 

0.39 

0.34 

30 

8.2 

8 

0.05 

0.13 

0.21 

0.28 

0.31 

0.33 

0.30 

48 

13.0 

5 

0.03 
0.03 

0.12      0.20 

0.29 

0.36 

0.42 
0.40 

0.42 

62 

16.7 

5 

0.09 

0.18 

0.27 

0.35 

0.41 

Experiment  II  Amblystoma  punctatum  Series  4600-5052 
The  eggs  were  hatched  on  March  29  to  April  4,  1913.  Opera- 
tions on  the  tail  were  made  on  May  7  in  numbers  4600-4752  and  on  May 
10  in  numbers  4800-5052.  The  removed  lengths  were  approximately 
Vio.  Vr,>  Vs!  V2  and  V,  of  the  tail  length.  Measurements  of  the  regen- 
erated tissue  were  made  at  2,  4,  6,  8-9,  10-11,  13,  15-16  and  17-18  days 
after  the  operation.  The  data  are  given  in  Tables  45  to  54  and  in  Figures 
36  to  51. 

The  salamander  larvae  are  much  more  irregular  in  their  regeneration 
as  well  as  in  ordinary  growth  than  frog  tadpoles.     The  measurements 


89)  RATE    OF    RECEXERATION—ZELENY  89 

in  the  present  experiment  were  made  on  killed  individuals  so  that  only 
a  single  regeneration  measurement  is  made  in  a  single  individual.  This 
procedure  also  tends  toward  a  greater  variability  in  the  data.  Tlie 
number  of  individuals  in  any  particular  measurement  also  is  less  tlian 
for  the  second  regeneration  of  frog  tadpoles. 

Xotwithstanding  all  these  unwelcome  factors  the  general  features 
of  regeneration  are  similar  to  those  for  the  tadpole  experiment.  The 
regenerated  lengtli  at  any  time  is  approximately  i^roportional  to  the 
removed  length.  It  is  true  even  in  the  earliest  measurements.  As 
for  frog  tadpoles  the  shorter  removals  have  proportionately  a  larger 
regeneration  than  the  others  at  practically  each  time  of  measurement. 
The  approach  to  equality  in  specific  lengths  is  true  only  of  tlie  lengths 
of  removal  equal  to  one-fifth  or  more  of  the  tail  length. 

At  two  days  the  regenerated  lengths  are  respectively  0.10,  0.15, 
0.15,  0.47  and  0.53  mm.  for  the  five  levels  of  removal.  They  give  specific 
lengths  of  0.07,  0.07,  0.04,  0.08  and  0.06  as  shown  Tabh>  45  aiul  Figures 
36  and  37. 

At  four  days  tlie  regenerated  lengths  are  0.12,  0.15,  0.30,  0.41  and 
0.40  mm.  and  the  specific  lengths  0.11,  0.07,  0.07,  0.07  and  0.05  as  shown 
in  Table  46  and  Figures  38  and  39. 

At  six  days  the  regenerated  lengths  are  0.32,  0.47,  0.62,  0.70  and 
1.02  mm.  and  the  specific  lengths  0.30,  0.20,  0.16,  0.12  and  0.11  as  shown 
in  Table  47  and  Figures  40  and  41. 

At  eight  to  nine  days  tlie  regenerated  lengths  are  0.40,  0.65,  0.80, 
1.40  and  1.52  mm.  and  the  specific  lengths  0.44,  0.28.  0.23,  0.23  and 
0.19  as  shown  in  Table  48  and  Figures  42  and  43. 

At  ten  to  eleven  days  the  regenerated  lengths  are  0.50,  0.63,  1.54, 
2.22  and  2.22  mm.  and  "the  specific  lengths  0.62,  0.26,  0.43,  0.41  and 
0.27  as  shown  in  Table  49  and  Figures  44  and  45. 

At  thirteen  days  the  regenerated  lengths  are  0.78,  0.92,-  1.74,  2.40 
and  3.60  mm  and  the  specific  lengths  0.74,  0.43.  0.48,  0.44  and  0.48  as 
shown  in  Table  50  and  Figures  46  and  47. 

At  fifteen  to  sixteen  days  the  regenerated  lengths  are  0.80,  1.30, 
1.37,  2.80  and  3.80  mm.  and  the  specific  lengths  0.67,  0.61,  0.40,  0.48  and 
0.54  as  shown  in  Table  51  and  Figures  48  and  49. 

At  seventeen  to  eighteen  days  the  regenerated  lengths  are  0.70, 
1.40,  1.60,  3.80  and  4.67  mm.  and  the  specific  lengths  0.67,  0.62,  0.41, 
0.66  and  0.57  as  shown  in  Table  52  and  Figures  50  and  51. 

A  summary  of  regenerated  lengths  is  given  in  Table  53  and  of 
specific  regenerated  lengths  in  Table  54. 

Since  the  experiment  was  closed  at  eighteen  days  and  since  the 
measurements  at  different  times  were  made  on  different  individuals  it 
is  not  possible  to  make  as  accurate  a  comparison  of  completeness  of 


90 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[90 


regeneration  as  in  the  case  of  the  frog  tadpoles.  For  the  three  shortest 
removals  regeneration  is  probably  completed  at  this  time  biit  this  is  not 
true  for  the  two  longest  ones.  In  this  respect  as  in  others  there  is  an 
agreement  with  the  former  experiment.  The  percent  of  the  removed 
tail  that  is  regenerated  is  greater  for  all  levels  than  in  the  frog  tadpoles. 
It  is  probable  also  that  if  the  longest  removals  had  been  allowed  to  com- 
plete their  regenerations  their  specific  regenerations  as  in  the  case  of 
the  frog  tadpoles  would  have  been  shown  to  be  greater  than  those  for 
medium  levels. 

TABLE  45 

Amblystoma  punctatum.        Series  4600-.50.52.        Average  tail  length  =10.9  mm. 

Regeneration:  2  days 


Percent  of 

tail  length 

Catalog 

Removed 

Regenerated 

Specific 

removed 

number 

length 

length 

length 

Average 

mm. 

mm. 

regenerated 

14 

5022 

1.5 

0.1 

Average   . 

1.5 

0.10 

0.07 

4641 

2.3 

0.2 

4741 

1.9 

0.1 

20 

4841 

2.2 

0.1 

5050b 

2.3 

0.2 

Average 

2.2 

0.15 

0.07 

4811 

3.9 

0.3 

4911 

3.3 

0.1 

32 

5012 

3.3 

0.05 

Average 

3.5 

6.0 

0.15 

0.04 

4601 

0.3 

4801 

6.0 

0.7 

53 

5001 

5.4 

0.4 

Average 

5.8 

0.47 

0.08 

4631 

9.5 

0.7 

4831 

9.1 

0.6 

81 

5032 

7.9 

0.3 

Average 

8.8 

0.53 

0.06 

91] 


RATE    OF    REGENERATION— ZELENY 


91 


The  data  from  botli  experiments  show  that  except  for  very  short 
removals  the  length  regenerated  in  a  given  time  is  approximately  pro- 
portional to  the  length  removed. 

TABLE  46 

Amblystoma  punctatum.       Series  4600-.^0.'2.         Average  tail  length=10.9   mm. 

Regeneration:  4  days 


Percent  of 

tail  length 

Catalog 

Removed 

Regenerated 

Specific 

removed 

number 

length 

length 

length 

Average 

mm. 

mm. 

regenerated 

4622 

0.9 

0.1 

4722 

0.8 

0.2 

4822 

1.5 

0.1 

10 

4922 

o.s 

0.1 

5024 

1.6 

0.1 

Average 

1.1 

0.12 

0.11 

4742 

2.4 

0.1 

21 

4842 

2.3 

0.2 

Average 

2.3 

0.15 

0.07 

4612 

3.7 

0.3 

4712 

3.6 

0.2 

37 

4812 

4.5 

0.4 

5012 

4.2 

0.3 

Average 

4.0 

0.30 

0.07 

4602 

6.0 

0.2 

4702 

6.0 

0.05 

4802 

6.2 

0.7 

55 

4902 

6.0 

0.5 

5004 

5.9 

0.6 

Average 

6.0 
9.3 

0.41 

0.07 

4632 

0.4 

4732 

8.5 

0.2 

4832 

10.9 

0.6 

76 

4932 

5.9 

0.4 

5034 

7.1 

0.4 

Average 

8.3 

0.40 

0.05 

92 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[92 


Amblystoma   punctatum. 


TABLE  47 
Series   4600-5052.       Average   tail  length=10.9   mm. 
Regeneration:   6  days 


Percent  of 

tail  lengtli 

Catalog 

Removed 

Regenerated 

Specific    . 

removed 

number 

length 

length 

length 

Average 

mm. 

mm. 

regenerated 

4623 

1.0 

0.3 

4723 

0.8 

0.2 

10 

4923 

1.6 

0.6 

1.1 

0.2 
0.32 

Average 

1.1 

0.30 

4643 

2.1 

0.7 

4743 

2.2 

0.2 

21 

4843 

2.1 

0.4 

4943 

2.8 

0.6 

Average 

2.3 

0.47 

0.20 

4613 

3.6 

0.6 

4713 

2.9 

0.6 

4820b 

4.4 

0.8 

35 

4913 

4.5 

0.6 

5013 

3.6 

0.5 

Average 

3.8 

0.62 

0.16 

4603 

6.1 

0.4 

4703 

6.7 

0.4 

54 

4803 

5.3 

1.4 

5003 

5.6 

0,6 

Average 

5.9 

0.70 

0.12 

4633 

8.8 

0.6 

4733 

8.2 

0.9 

82 

4833 

10.6 

1.8 

5033 

7.9 

0.8 

Average 

8.9 

1.02 

0.11 

93] 


RATE    OF    REGENERATIOS  —  ZELESY 


93 


Amblystoma    punctatum 
Regeneration 


TABLE  48 
Series    4600-5052      Average    tail    length=10.9 
8-9  days  (8  for  4800-5052,  9  for  4600-4752) 


Percent  of 

tail  length 
removed 
Average 

Catalog 
number 

Removed 

length 

mm. 

Regenerated 

length 

mm. 

Specific 

length 

regenerated 

8 

4724 
4824 
502G 

0.7 
1.1 
1.0 

0.2 
0.7 
0.3 

Average 

0.9 

0.40 

0.44 

21 

4644 
4844 
4944 
5045 

2.3 
2.3 
2.2 
2.3 

0.6 
1.0 
0.7 
0.3 

Average 

2.3 

0.65 

0.28 

31 

4614 
4624 
4714 
4814 
4914 
5016 

3.0 
3.0 
3.4 
3.7 
3.2 
4.3 

0.8 
0.4 
1.2 
1.0 
0.6 
0.8 

Average 

3.4 

0.80 

0.23 

56 

4604 
4704 
4804 
4904 
5006 

6.0 
6.3 
5.9 
5.4 
6.8 

1.8 
1.7 
1.4 
0.9 
1.2 

Average 

6.1 

1.40 

0.23 

75 

4634 
4734 
4834 
4934 

8.3 
8.0 
9.0 
7.5 

2.1 
1.3 
1.6 
1.1 

Average 

8.2 

1.52 

0.19 

94 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[94 


TABLE  49 

Amblj'stoma    punctatum       Series    4600-5052       Average    tail    lengtli=10.9    mm. 

Regeneration:   10-11  days  (10  for  4800-5052,  11  for  4600-4752) 


Percent  of 

tail  length 

Catalog 

Removed 

Regenerated 

Specific 

removed 

number 

length 

length 

length 

Average 

mm. 

mm. 

regenerated 

4725 

0.6 

0.3 

4825 

0.8 

0.6 

7 

5027 

1.0 

0.6 

Average 

0.8 

0.50 

0.62 

4746 

2.6 

0.4 

4845 

2.6 

1.0 

23 

5046 

2.2 

0.5 

Average 

2.5 

3.0 

0.63 

0.26 

4620b 

1.9 

4715 

3.0 

1.8 

4815 

4.3 

2.0 

33 

4920 

3.6 

1.2 

5017 

3.9 

0.8 

Average 

3.6 

1.54 

0.43 

4605 

5.2 

2.8 

4705 

4.6 

1.4 

4805 

6.3 

2.8 

50 

4910b 

5.0 

1.9 

5007 

6.0 

2,2 

Average 

5.4.. 

2.22 

0.41 

4735 

7.5 

2.5 

4835 

9.4 

2.9 

74 

4935 

7.6 

1.3 

5037 

8.1 

2.2 

Average 

8.1 

2.22 

0.27 

95] 


RATE    OF    REGENERATION  — ZELENY 


95 


Amblystoma   punctatum.       Series   4600-5052.       Average   tail   length= 
Regeneration:   13  days 


Percent  of 

tail  length 

removed 

Average 

Catalog 
number 

Removed 

length 

mm. 

Regenerated 
length 
mm. 

Specific 

length 

regenerated 

10 

4626 

4726 

4830b 

4926 

5028 

1.4 
1.0 
1.0 
1.0 
0.9 

0.8 
0.6 
0.7 
0.9 
0.9 

Average 

1.1 

0.78 

0.74 

19 

4646 
4745 
4846 
4946 

1.9 
2.2 
2.6 
1.9 

1.4 
0.8 
1.0 
0.5 

Average 

2.1 

0.92 

0.43 

32 

4616 
4716 
4816 
4916 
5018 

3.6 
3.2 
3.9 
3.7 
3.7 

1.8 
2.0 
2.5 
1.6 
0.8 

Average 

3.6 

1.74 

0.48 

50 

4706 
4806 
4910 
5008 

6.4 
5.8 
5.0 
4.5 

2.3 
■  2.9 
2.5 
1.9 

Average 

5.4 

2.40 

0.44 

69 

4636 
4740b 
4936 
5038 

8.1 
7.7 
7.4 
6.7 

3.4 
4.7 
3.5 
2.8 

Average 

7.5 

3.60 

0.48 

96 


ILLINOIS    BIOLOGICAL    MONOGRAPHS 


[96 


TABLE  51 

Amblystoma   punctatum.       Series   4600-5052.       Average   tail   length^lO.9   mm. 

Regeneration:  15-16  days  (15  for  4800-5052,  16  for  4600-47g2) 


Percent  of 

tail  length 

removed 

Average 

Catalog 
number 

Removed 

length 

mm. 

1.2 
1.2 

Regenerated 

length 

mm. 

Specific 

length 

regenerated 

11 

4927 
5029 

0.8 
0.8 

Average 

1.2 

0.80 

0.67 

19 

4647 

4747 

4847 

4950b 

5049 

1.9 

2.7 
2.4 
1.9 
1.8 

1.5 
1.7 
1.0 
1.2 
1.1 

Average 

2.1 

1.30 

0.61 

32 

4617 
4717 
4917 
5019 

3.1 
3.5 
3.2 
4.1 

1.4 
1.3 
1.8 
1.0 

Average 

3.5 

1.37 

0.40 

53 

4607 
4807 
4817 
5009 

5.7 
5.7 
5.2 
6.6 

2.7 
2.9 
2.6 
3.0 

Average 

5.8 

2.80 

0.48 

64 

4937 

7.0 

3.8 

Average 

7.0 

3.80 

0.54 

97] 


RATE    OF    REGENERATION —ZELENY 


97 


TABLE   52 

Amblystoma  punctatura.       Series   4600-5052.       Average   tail   Iength=10.9   mm. 

Regeneration:  17-18  days  (18  for  4800-5052,  17  for  4600-4752) 


Percent  of 

tail  lengtti 

Catalog 

Removed 

Regenerated 

Specific 

removed 

number 

length 

length 

length 

Average 

mm. 

mm. 

regenerated 

4828 

1.0 

0.8 

10 

4929 

1.1 

0.6 

Average 

1.0 

0.70 

0.67 

4648 

2.1 

1.5 

4749 

2.6 

2.1 

4848 

2.1 

1.1 

20 

4949 

2.2 

1.3 

5050 

2.2 

1.0 

Average 

2.2 

1.40 

0.62 

4718 

3.9 

1.6 

36 

Average 

3.9 

1.60 

0.41 

4608 

5.4 

4.2 

4708 

6.6 

4.1 

53 

4808 

5.4 

3.1 

Average 

5.8 

3.80 

0.66 

4838 

9.4 

5.0 

4939 

6.4 

4.5 

76 

5040 

9.0 

4.5 

Average 

8.3 

4.67 

0.57 

ILLINOIS    BIOLOGICAL    MONOGRAPHS 


TABLE  53 

Amblystoma  punctatum       Series   4600-5052       Summary       Regenerated   lengths 

(Tables  45  to  52) 


Percent  of 

tail   length 

removed 

Average 

Length 
removed 

mm. 
Average 

Average    le 

ngth    regenerated    In 

mm. 

2 
Days 

4 
Days 

0.12 

0.15 

0.30 

6 
Days 

8-9 
Days 

10-11 
Days 

13 
Days 

0.78 

0.92 

15-16 
Days 

17-18 
Days 

10 

1.1 

0.10 

0.32 

0.40 
0.65 
0.80 
1.40 
1.52 

0.50 
0.63 

0.80 

0.70 

21 

2.2 

0.15 

0.47 

1.30 

1.40 

34 

3.7 

0.15 

0.62 

1.54 

1.74 

1.37 

1.60 

53 

5.8 

0.47 

0.41 
0.40 

0.70 

2.22 

2.40 
3.60 

2.80 

3.80 

74 

8.1 

0.53 

0.94 

2.22 

3.80 

4.70 

TABLE  54 

Amblystoma  punctatum    Series  4600-5052    Summary    Specific  lengths  regenerated 

(Tables  45  to  52) 


Percent  of 

Length 
removed 

mm. 
Average 

Ave 

rage  sp 

ecific  regenerated  lengths 

tail   length 
removed 
Average 

2 

Days 

4 
Days 

6 
Days 

8-9 
Days 

10-11 
Days 

13 
Days 

15-16 
Days 

17-18 
Days 

10 

1.1 

0.07 

0.11 

0.30 
0.20 
0.16 

0.43 

0.62 

0.74 

0.67 

0.67 

21 

2.2 

0.07 
0.04 

0.06 

0.28 

0.26 

0.43 

0.61 

0.62 

34 

3.7 

0.07 

0.23 

0.43 

0.48 
0.44 
0.48 

0.40 

0.41 

53 

5.8 

0.08 

0.07 

0.12 
0.11 

0.23 

0,41 
0.27 

0.48 
0.54 

0.66 

74 

8.1 

0.06 

0.15 

0.19 

0.57 

99] 


RATE    OF    REGENERATION —ZELEKY 


99 


2.2  3.5  5.8 

Lengths  removed  in  mm. 


Figure  36    Amblystoiiia   i^iiiictafuiii       Lengths  regenerated     Two  days 


mm. 
0.10 


<c  Figure  37 


1.5      2.2  3.5  5.8  8.8 

— >-      Lengths  removed  in  mm. 
Amblystoma   fmctatuiu       Specific  lengths  regenerated    Two  days 


0.67 


c  1.1  2.3  4.0  6.0  8 

kJ  — >      Lengths  removed  in  mm. 

Figure  38    Amblystoiiia   fuiutatuiii      Lengths  regenerated     Four  days 


S  Figure  39 


1.1  2.3  4.0  6.0  8.3 

— >■      Lengths  removed  in  mm. 
Amblystoma   puiictatuin       Specific  lengths  regenerated      Four  days 


100 


ILLINOIS   BIOLOGICAL    MONOGRAPHS 


HOC 


>4 

Figure  40 
o 
£  mm. 

oi 

to  0.30 

Si  0.20 

»  0.10 


®  Figure  41 


mm. 
1.33 


0.67 


1.1  2.3  3.8  .0.9 

— >-      Lengtlis  removed  in  mm. 

Amblystoma    puuctatiiiii        Lengtlis  regenerated 


Six  dayy 


1.1  2.3  3.8  5.9  8.9 

— >-      Lengths  removed  in  mm. 

Amblystoma   punctatuin       Specific  lengths  regenerated      Six  days 


0.9 


6.1 


8.2 


2.3  3.4 

— >-      Lengths  removed  in  mm. 
Figure  42     Aiiiblystoiiia    puiirtatitin       Lengths  regenerated     Eight  to  nine  days 

'S         mm. 
g         0.50 

g  0.40 

£  0.30 

5  0.20 

S  0.10 


I 


^  0.9  2.3  3.4  6.1  8.2 

— >      Lengths  removed  in  mm. 
Figure   43      Amblystoma   pnnctatuin         Specific   lengths   regenerated      Eight   to 
nine  days 


101] 


RATE   OF  REGEXERATION—ZELENY 


101 


1.33 


0.8 


8.1 


Figure  44 


2.5  3.6  5.4 

— >■      Lengths  removed  in  mm. 
Amblystoiua   l^unctatum      Lengths  regenerated     Ten  to  eleven  days 


en 


mm. 
0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


0.8 


2.5  3.6  5.4 

— >      Lengths  removed  in  mm. 
Figure    45     Ainhlysioma   punctatum  Specific    lengths    regenerated 

eleven  days 


102 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 


[102 


mm. 
3.33 


2      2.00 


1.1  2.1  3.6  5.4  7.5 

— >-      Lengths  removed  in  mm. 
Figure  46    Ainblystoiiia   pniiitatiini       Lengths  regenerated     Thirteen  days 


mm. 
0.70 

0.60 

0.50 

0.40 

0.30 

0.20 

0.10 


Figure  47 


1.1  2.1  3.6  5.4  7.5 

— y      Lengths  removed  in  mm. 
Amblystoma   punctatum    Specific  lengths  regenerated    Thirteen  days 


103] 


RATE  OF  REGEXERATIOX—ZELEKY 


103 


mm. 
4.00 


1.2         2.1  3.5  5.8  7.0 

— >-      Lengths  removed  In  mm. 
Figure  48      Amblysioma   pnnctatuiK.       Lengths  regenerated      Fifteen  to  sixteen 


S    09"0 
£     0.50 


0.30 


1.2 


7.0 


2.1  3.5  5.8 

— >■      Lengths  removed  in  mm. 
Figure  49     Amblystoma   i>unctat\im       Specific   lengths  regenerated     Fifteen  to 
sixteen  days 


104 


ILLINOIS   BIOLOGICAL   MOXOGRAPHS 


[104 


mm. 
4.67 


2.67 


1 


1.0  2.2  3.9  5.8  8.3 

— >-  Lengths  removed  in  mm. 

Figure  50     Ainblystoma  punctatuin      Lengths  regenerated     Seventeen  to  eight- 
een days 


W 


mm. 

0.70 

0.60 
0.50 
0.40 
0.30 
0.20 
0.10 


1.0 


5.8 


2.2  3.9 

— >      Lengths  removed  in  mm. 
Figure  51      Ainblystoma   punctatuiti        Specific  lengths  regenerated 
to  eighteen  days 


I 


105]  RATE  OF  REGEXERATION—ZELENY  105 


Discussion 

That  the  level  of  the  cut  has  an  important  influence  upon  the  rate 
of  regeneration  has  been  made  out  by  a  number  of  investigators  (Spal- 
lanzani  1768,  King  1898,  Morgan  1906,  Stockard  1908,  Ellis  1909,  Morgu- 
lis  1909a,  b,  and  others).  Their  work  indicates  that  regenerations  from 
deeper  levels  are  on  the  whole  more  rapid  that  from  more  superficial  ones. 
The  data  obtained  from  the  present  experiments  confirm  tliis  conclusion 
and  make  possible  a  further  analysis  of  the  relation.  They  show  that 
in  the  regeneration  of  the  tail  of  amphibian  larvae  there  is  a  striking 
relation  between  the  level  of  the  cut  and  the  rate  of  regeneration. 
Within  wide  limits  the  length  regenerated  is  directly  proportional  to 
the  distance  of  the  cut  surface  from  tlie  original  tip  of  the  tail.  Within 
these  limits  therefore  regeneration  at  any  particular  time  after  the 
operation  has  the  same  degree  of  completeness  from  all  levels  of  injury. 

An  anal.ysis  of  the  progress  of  the  regeneration  brings  out  the  fact 
that  two  distinct  periods  are  to  be  recognized  in  rate  of  regeneration 
in  its  relation  to  level  of  the  cut.  During  the  first  two  to  four  days 
after  the  operation  regeneration  is  confined  to  cell  migration  from  the 
old  tissues  without  cell  di\'ision.  During  this  period  in  the  frog  tad- 
poles there  is  no  essential  difference  in  lengtli  regenerated  at  the  differ- 
ent levels  and  the  specific  rate  is  therefore  much  greater  after  shorter 
than  after  longer  removals.  In  the  second  period  with  the  initiation 
of  rapid  cell  multiplication  the  rate  of  regeneration  is  greater  the  deeper 
the  level  and  furthermore  is  directly  proportional  to  the  length  removed. 
As  soon  as  the  bulk  of  material  produced  by  cell  division  is  considerably 
greater  than  that  which  was  prodviced  by  cell  migration  there  is  an 
approach  to  constancy  in  specific  length  regenerated.  This  holds  for  all 
except  the  shortest  removals.  After  the  shortest  removals  the  total 
regeneration  is  so  small  in  amount  that  a  large  part  of  it  is  made  up 
of  the  original  migrated  material.  Therefore  from  these  levels  the  spe- 
cific regenerated  lengtlis  are  greater  than  from  the  deeper  levels  even 
at  a  late  period  of  regeneration. 

A  further  complication  is  introduced  by  the  fact  that  regeneration 
is  not  complete.  Only  a  certain  per  cent  of  the  removed  length  is  re- 
placed and  the  end  of  the  process  is  reached  .sooner  after  the  shorter 
than  after  the  longer  removals.  From  the  deepest  levels  regeneration 
is  still  proceeding  when  it  has  stopped  from  the  medium  and  shallowest 
ones.  When  the  process  is  completed  in  all  cases  the  specific  length  is 
therefore  slightly  greater  after  botli  the  longest  and  the  shortest  re- 
movals tlian  after  medium  ones. 

As  to  the   cause  of  the   tliffei-ence   in   rate   at   the   different    levels 


106  ILLINOIS   BIOLOGICAL   MONOGRAPHS  [106 

little  more  can  be  said  than  that  it  does  not  seem  to  be  due  to  inherent 
differences  in  the  cells  at  the  different  levels.  If  differentiation  in  the 
tail  proceeded  from  the  tip  toward  the  base,  the  more  rapid  rate  fi-om 
the  more  basal  levels  might  be  explained  by  the  more  embryonic  char- 
acter of  the  cells  at  tliese  levels.  As  the  tip  is  approached  the  material 
would  become  more  and  more  inert.  There  is  however  no  evidence 
tliat  differentiation  proceeds  in  this  way  in  this  case. 

The  progressive  increase  in  rate  with  depth  of  level  of  tlie  cut  is 
undoubtedly  due  to  reactions  which  involve  a  more  central  control,  a 
co-ordination  of  the  functional  activity  as  a  whole.  The  period  of  cell 
migration  probably  is  only  slightly  subject  to  such  control.  It  is  a 
period  in  which  the  response  is  largely  local  in  character  and  there  is 
correspondingly  little  if  any  difference  at  the  different  levels.  The 
rate  of  cell  division  which  is  the  important  factor  during  the  period 
of  rapid  increase  in  length  is  however  undoubtedy  under  central  control. 

Summary 

1.  In  frog  and  salamander  larvae  with  removed  tail  lengths  of 
one-fifth  to  two-thirds,  the  general  rule  holds  that  the  length  regenerated 
in  a  given  time  is  proportional  to  the  length  removed,  or  in  other  words 
the  length  regenerated  per  unit  of  removed  lengtli  is  a  constant. 

2.  An  analysis  of  the  data  shows  however  that  this  applies  only 
to  the  material  produced  by  active  cell  division. 

3.  During  the  first  four  days,  in  frog  tadpoles,  when  the  regener- 
ating part  is  made  up  almost  entirely  of  cells  that  have  migrated  from 
the  old  tissues  without  division  there  is  no  such  relation  between  length 
i-emoved  and  length  regenerated.  The  length  of  new  material  at  this 
time  is  not  strikingly  different  for  the  different  levels  and  the  process 
seems  to  be  a  local  response  of  the  cells  to  the  injury.  The  length 
regenerated  per  unit  of  removed  length  is  greater  at  this  time  for  the 
shorter  than  for  the  longer  removals. 

4.  Since  comparatively  a  large  part  of  the  regenerating  material 
after  the  shorter  removals  is  made  up  of  migrated  cells  even  at  the 
later  periods  it  follows  that  the  specific  regenerations  from  these  levels 
are  greater  than  from  the  deeper  ones. 

5.  During  the  later  periods  the  specific  regenerated  lengths  tend 
to  be  higher  after  both  the  shortest  and  the  longest  removals  than  after 
medium  ones.  In  tlie  case  of  the  shortest  ones  this  is  due  to  the  rela- 
tivel.v  large  part  of  the  whole  regenerated  tail  that  is  made  up  of  mi- 
grated cells.  In  the  case  of  the  longest  removals  it  is  due  to  the  fact 
that  regeneration  continues  for  a  time  after  it  has  stopped  in  the  medium 
ones. 


107]  RATE  OF  REGENERATION— ZELENY  107 

6.  It  does  not  seem  probable  that  the  differences  in  length  regener- 
ated at  different  levels  can  be  due  to  differences  in  tlie  original  character 
of  the  cells  involved  in  the  process.  Such  a  well  graduated  difference 
in  cell  capacities  is  difficult  to  conceive.  The  process  must  be  iinder  a 
more  central  control,  probably  connected  with  general  functional 
activity. 


108  ILLIXOIS   BIOLOGICAL    MOXOGRAPHS  [108 


PART  IV 

THE  CHANGE  IN  RATE  OF  REGENERATION  DURING  THE 

REGENERATIVE  PROCESS 

The  present  experiments  were  undertaken  in  extension  of  previous 
studies  on  the  change  in  rate  throughout  the  regenerative  cycle.  This 
previous  work  showed  that  the  increase  in  amount  of  material  during 
regeneration  follows  the  general  rule  of  increase  during  an  ordinary 
life  cycle.  The  rate  is  at  first  very  slow,  then  increases  very  rapidly 
to  a  maximum,  then  declines  rapidly  at  first  and  then  more  and  more 
slowly  as  zero  is  approached. 

Frog  tadpoles  and  salamander  larvae  were  used  in  the  present 
study.  Large  tadpoles  of  Bona  clamitans  which  remained  fairly  con- 
stant in  size  during  the  course  of  the  experiments  were  found  to  be  the 
most  satisfactory.  The  results  obtained  from  them  were  uniform  enough 
for  an  analysis  of  the  change  in  rate.  The  salamander  larvae  showed 
a  great  variation  in  rate  from  day  to  day  apparently  associated  with 
external  factors  such  as  food  and  temperature.  The  data  obtained  from 
them  are  however  of  interest  in  comparison  with  the  frog  tadpole  results. 

The  experiments  will  be  taken  up  in  turn  beginning  with  the  series 
containing  the  largest  number  of  individuals  and  giving  the  most  iini- 
form  results. 

Experiment    I       Rana   clamitans      Second   regenerations    of    the 
TAIL       Series  3676-3765 

The  tadpoles  were  collected  on  December  9,  1911  and  first  remov- 
als were  made  on  December  22  and  second  removals  on  January  8. 
Measurements  were  taken  4,  6,  8,  10,  12i/o  and  56  days  after  the  opera- 
tion. The  operations  were  made  at  six  different  levels,  the  removals 
approximating  6,  10,  18,  31,  49  and  67  per  cent  of  the  tail  length.  The 
first  of  these  removals  averaged  1.5  mm.  and  four  individuals  with 
completed  measurements  are  available,  the  next  averaged  2.8  mm.  with 
seven  individuals,  the  third  4.9  mm.  with  five,  the  fourth  8.4  mm.  with 
ten,  the  fifth  13.1  mm.  with  eight  and  the  sixth  18.1  mm.  with  ten 
individuals.  The  rates  per  day  for  each  level  during  each  period  are 
given  in   table   55  and  in  graphic  form  in  figure  52.     The  maximum 


109] 


RATE  OF  REGEXERATIOX—ZELEXY 


109 


2        5      7      9    11>4      1">U 
— >■      Days  after  the  operation 
Figure  52     Rates  of  second  regenerations  of  the  tail  per  day  at  different  times 
after  the  operation  for  six  different  levels      Rana  damitans      The  removed 
lengths  are  1.5,  2.8,  4.9.  8.4,  13.1  and  18.1  mm. 


110 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


rate  is  reached  during  the  period  between  four  and  six  daj's  at  three 
of  the  levels  and  between  six  and  eight  daj's  at  the  other  three.  The 
rise  in  rate  is  very  rapid  and  the  decline  also  rapid. 

As  discussed  in  the  preceding  section  on  the  effect  of  the  level  of 
the  cut,  the  rate  of  regeneration  increases  with  depth  of  the  level  and 
the  increase  is  such  that  in  general  the  specific  length  or  length  regener- 
ated per  unit  of  removed  lengtli  is  approximately  a  constant.  A  reduc- 
tion of  the  rates  to  specific  rates  therefore  gives  an  opportunity  for 
averaging  the  different  levels  together.  The  resultant  average  is  based 
upon  a  sufficiently  large  number  of  individuals  to  give  a  considerable 
degree  of  smoothness  in  the  curve  of  rate.     The  data  for  specific  rate 


2  nd 


2  5  7  9  11%  151/4 

— >      Days  after  the  operation 
Figure  53.     Specific  rates  of  first  and  second  regenerations  at  different  times 
after   tlie   operation        Rana  claniitans       Tail   regeneration      Upper   figure, 
second  regenerations;   lower,  first  regenerations. 

are  given  in  Table  56.  The  average  specific  rates  for  all  six  levels  to- 
gether are  0.019  mm.  during  the  0  to  4  day  period,  0.066  during  the 
4  to  6  day  period,  0.0.51  for  6  to  8  days,  0.03.3  for  8  to  10  days,  0.017  for 
10  to  12i/o  days,  0.001  for  12yo  to  18  days  and  —0.001  for  18  to  56 
days.  This  change  in  rate  is  represented  graphically  in  the  upper  part 
of  Figure  53.  For  the  four  deepest  levels  the  averages  are  given  in  a 
separate  column  of  Table  56.    Tliey  exclude  the  two  lowest  levels  which 


Ill] 


RATE  OF  REGEXERATIOX—ZELEA'V 


depart  considerably  from  the  others  iu  specific  rate.  There  is  how- 
ever no  essential  difference  in  the  two  sets  of  values  as  regards  the  form 
of  the  rate  curve. 

The  change  in  rate  of  regeneration  or  acceleration  of  rate  from  any 
period  to  the  succeeding  one  is  shown  iu  Table  57  in  which  the  period 
of  change  is  represented  by  the  middle  days  of  the  two  periods  which 
are  being  compared.  The  average  of  all  the  levels  shows  the  acceler- 
ation to  be  +0.095  mm.  from  the  2  to  tlie  5  day  period,  — 0.015  for  5  to 
7  days,  —0.030  for  7  to  9  days,  —0.058  for  9  "to  111,4  days,  —0.028  for 
111/4  to  151/4  days  and  — 0.001  for  I514  to  37  days.  It  is  only  between 
the  first  two  periods  that  acceleration  of  rate  is  a  plus  quantity.  Dur- 
ing all  the  others  it  is  minus,  the  most  rapid  rate  of  decrease  coming 
between  9  and  111/4  days. 

The  accelerations  of  specific  rate  are  more  reliable  measures  for 
obtaining  averages  including  tlie  different  periods.  Such  values  are 
given  in  Table  58  and  iu  graphic  form  in  Figure  54.  They  give  a  result 
in  the  relation  of  the  periods  to  each  other  essentially  similar  to  that 
above.     The  average  accelerations  of  specific  rate  are   -(-0.014  for  the 


Figure  54. 

tail  in 


6       8       10       1314  26 

— >-      Days  after  the  operation 
Acceleration  of  specific  rate     First  and  second  regenerations  of  the 
Rana  claiiiitans     Unbroken  line=First  regeneration     Broken  Iine= 


Second  regeneration. 

2  to  5  day  periods,  — 0.004  for  5  to  7  days,  — 0.009  for  7  to  9  days, 
—0.0085  for  9  to  II14  days,  —0.003  for  II14  to  I514  days  and  0.000 
for  1514  to  37  days.  The  first  period  is  the  only  one  with  a  plus  accel- 
eration. The  greatest  minus  acceleration  comes  between  the  7  and  the 
9  day  periods  instead  of  9  to  111/4  days.  Averaging  only  the  regener- 
ations for  the  four  deepest  levels  which  show  a  constant  specific  rate 


112 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[112 


the  values  are  respectively  +0.011,  0.000,  —0.005,  —0.006,  —0.004  aud 
0.000,  putting  the  greatest  rate  of  decrease  between  the  9  and  the  III/4 
day  periods. 

An  examination  of  the  curves  of  specific  rate  and  a  comparison 
with  the  facts  of  histogenesis  shows  that  acceleration  of  rate  is  a  plus 
quantitj''  only  during  the  period  before  active  differentiation  of  the 
cells,  i.  e.  until  the  end  of  the  fifth  or  seventh  day.  As  soon  as  tissue 
differentiation  is  fairly  begun  the  retarding  influence  is  apparent  and 
by  the  nintli  to  eleventh  days  when  muscle  fibres  and  other  cells  are  in 
full  process  of  differentiation  the  negative  acceleration  is  at  its  height. 

Following  the  percentage  increment  method  used  by  Minot  (1908) 
for  ordinar.y  growth  and  using  length  instead  of  weight  becaiise  the  latter 
could  not  be  determined  with  sufficient  accuracy  the  results  given  in 
Table  59  are  obtained.  The  values  for  the  six  periods  excluding  the  first 
one  are  106,  28,  12,  5  and  0.  The  regenerated  material  present  at  the 
end  of  four  days  is  made  up  almost  wholly  of  cells  that  have  migrated 
from  the  old  tissues  and  have  not  as  yet  undergone  division.  After  the 
fourth  day  the  additions  to  regenerated  material  are  almost  wholly 
the  result  of  cell  division.  From  the  end  of  the  fourth  to  the  end  of 
the  sixth  day  the  material  is  on  the  average  more  than  doubled  in  length 
each  day.  After  this  time  the  percentage  increment  decreases  rapidly. 
The  change  from  period  to  period  is  represented  in  graphic  form  in 
Figure  55.    The  curve  is  a  logarithmic  one  quite  similar  to  that  obtained 


5  7  9  11%  15% 

— >-      Days  after  the  operation 
Figure  55      Percentage  increment  per  day  at  different  periods  after  the  opera- 
tion     First  and  second  regenerations  of  the  tail  of     Rana  danntans      U^^ 
broken  line=first  regeneration.     Brolten  line=second  regeneration. 


113J 


RATE   OF  REGENERATION  — ZELENY 


113 


hy  ilinot  for  growth.  It  should  however  be  poiuted  out  that  both 
regeueration  aud  ordiuary  growth  undoubtedh'  have  a  verj'  rapidly 
aseeudiug  branch  of  the  curve  if  the  very  beginuings  of  the  processes 
are  included. 

TABLE  55 

Rana  clamitans       Series  3676-3765       Second  regenerations 

Rate  of  regeneration  of  tail  per  day  at  different  times  during  the  regenerative 

process  for  six  different  levels 


Percent   of 

tail   length 

removed 

6 

10 

18 

31 

49 

67 

Length 
removed 
in   mm. 

1.5 

2.8 

4.9 

8.4 

13.1 

18.1 

No.    of    in- 
dividuals 

4 

7 

5 

10 

8 

10 

Days 

0-  4 

0.05 

0.10 

0.06 

0.10 

0.12 

0.13 

4-  6 

0.20* 

0.20* 

0.23 

0.34 

0.40 

0.91* 

6-  8 

0.14 

0.15 

0.25* 

0.35* 

0.50* 

0.70 

8-10 

0.05 

0.10 

0.10 

0.25 

0.12 

0.50* 

0.70 

10-12  V4 

0.00 

0.00 

0.08 

0.28 

0.44 

12%-18 

0.00 

—0.02 

—0.02 

0.00 

0.07 
0.01 

0.15 

18-56 

0.00 

—0.01 

0.00 

0.00 

0  00 

114 


ILLIXOIS   BIOLOGICAL   MONOGRAPHS 


Rana  clamitans       Series  3676-3765       Second   regenerations 
Specific  rates  at  different  levels  at  different  times 


Percent  of 
tail  length 
removed 

6 

10 

18 

31 

49 

67 

18.1 

Average 

of 

all 

levels 

Average 
of  four 
longest 
remov- 

Length 
removed 
in  mm. 

1.5 

2.8  ' 

4.9 

8.4 

13.1 

No.  of  in- 
dividuals 

4 

7 

5 

10 

8 

10 

Days 

0-  4 

0.037 

0.035 

0.012 

0.012 

0.010 
0.045* 

0.007 

0.019 

0.010 

4-  6 

0.135* 

0.080* 

0.045 

0.040 

0.050* 

0.066* 

0.045* 

8-10 

0.035 

0.035 

0.025 

0.030 

0.035 

0.035 

0.051 

0.042 

6-  8 

0.090 

0.045 

0.050* 

0.045* 

0.040 

0.040 

0.033 

0.032 

10-121/2 

0.000 

0.000 

0.025 

0.015 

0.030 

0.030 

0.017 

0.025 

12%-18 

0.000 

—0.005 

—0.004 

0.000 

0.005 
0.001 

0.009 

0.001 
—0.001 

0.002 

18-56 

—0.002 

—0.004 

0.001 

0.000 

0.000 

0.000 

115] 


RATE   OF  RECEXERATIOK—ZELEKY 


115 


TABLE   57 

Rana  clamitans       Series   3676-3765       Second   regenerations 
Acceleration  ot  rate  of  regeneration  of  tail  per  day  at  different  times  during 
the  regenerative  process  for  six  different  levels 

Percent   of 

tail    length 

removed 


Length 
removed 
in  mm. 


No.  of  in- 
dividuals 


Middle   ot 

periods 

Days 

2-  5 


9-11% 


ll%-15y4 


151/4-37 


-0.05' 
-0.03 
-0.04* 
-0.02 
0.00 
-0.00 


10 

18 

2.8 

4.9 

7 

5 

-I-0.03* 

+  0.06* 

—0.02 

-1-0.01 

—0.02 

-0.07* 

—0.04* 

—0.01 

—0.00 

—0.02 

—0.00 

+  0.00 

+  0.08* 

+0.00 

—0.05 

—0.06* 

—0.03 

—0.00 


+  0.09' 
+0.05 
0.00 
—0.10* 
—0.05 
—0.00 


+0.26' 


-0.07 
-0.01 


Average 

of 

all 

levels 


116 


ILLINOIS   BIOLOGICAL    MONOGRAPHS 


[116 


TABLE  58 
Rana  clamitans       Series  3676-3765       First  regenerations 
Acceleration  of  specific  rate  of  regeneration  of  the  tail 


Percent  of 

tail 

lengtli 

removed 

Length 
removed 
In  mm. 

No.   of  in- 
dividuals 

Days 

2-  5 


9-1114      —I 


ii%-i5y4 


15%-37 


6 

10 

18 

31 

49 

67, 
18.1 

Average 
of     . 
all 
levels 

1.5 

2.8 

4.9 

8.4 

13.1 

4 

7 

5 

10 

8 

10 

+  0.033* 

+  0.011* 

+0.012* 

+0.010* 

+0.007* 

+  0.014* 

+0.014* 

—0.020 

—0.007 

+0.002 

0.000 

+  0.004 

—0.006 

—0.004 

—0.027* 

—0.007 

—0.014* 

—0.006 

0.000 

0.000 

—0.009* 

—0.013 

-0.014* 

—0.002 

—0.007* 

-0.008* 

—0.007 

—0.008 

0.000 

0.000 

—0.004 

-0.004 

—0.004 

—0.004 

—0.003 

0.000 

0.000 

0.000 

0.000 

0.000 

—0.001 

0.000 

Average 
of  four 
deepest 
levels 


+0.011' 


117] 


RATE   OF  REGENERATION  — ZELENY 


117 


TABLE   59 

Rana  clamitans       Series  3676-3765       First  regenerations 

Percentage  increment  of  regenerating  tail  per  day  during  each  time  period  for 

six  different  levels 


Percent  of 

tail    length 

6 

10 

18 

31 

49 

67 

removed 

Average 

Length 

of 

removed 

1.5 

2.8 

4.9 

8.4 

13.1 

18.1 

ail 

in  mm. 

levels 

No.  of  in- 

dividuals 

4 

7 

5 

10 

8 

10 

Days 

4-  6 

91 

53 

96 

142 

80 

175 

106 

6-  8 

23 

19 

36 

32 

29 

30 

28 

8-10 

5 

9 

8 

14 

19 

19 

12 

10-12% 

0 

0 

6 

5 

8 

9 

5 

12>4-18 

0 

—2 

—1 

0 

2 

2 

0 

18-56 

—0 

—1 

+0 

—0 

+  0     ( 

+0 

0 

118  ILLISOIS   BIOLOGICAL   MONOGRAPHS  [118 

Experiment  II      Raxa  clamitans      First  regenerations  op  the  tail, 
Series  3676-3765 

The  tadpoles  were  collected  on  December  9,  1911,  and  the  tail  remov- 
als were  made  on  January  8.  Measurements  were  taken  4,  6,  8,  10,  12%, 
18  and  56  days  after  the  opei'ations.  The  operations  were  at  six  levels 
approximating  6,  10,  17,  30,  48  and  62  per  cent  of  the  original  tail 
length.  For  the  first  of  these  levels  only  two  individuals  with  an  average 
removal  of  1.5  mm.  are  available,  for  the  second  five  individuals  with 
2.6  mm.,  for  the  third  three  with  4.6  mm.,  for  the  fourth  eight  with  8.2 
mm.,  for  the  fifth  five  with  13.0  mm.  and  for  the  sixth  five  with  16.7  mm. 
The  rates  of  regeneration  per  day  are  given  in  table  60  and  the  graphs 
for  the  rates  in  Figure  56. 

Tlie  specific  rates  are  given  in  Table  61.  Averaging  these  values 
so  as  to  include  all  the  different  levels  for  each  period  the  specific  rates 
are  0.018  for  0  to  4  days,  0.046  for  4  to  6  days,  0.057  for  6  to  8  days, 
0.037  for  8  to  10  days,  0.026  for  10  to  I21/2  days,  0.002  for  121/0  to  18 
days  and  — 0.001  for  18  to  56  days.  The  graph  is  shown  in  the  unbroken 
line  in  Figure  53.  Using  only  the  four  deepest  levels  the  average  specific 
rates  are  respectively  0.013,"  0.042,  0.045,  0.036,  0.025,  0.006  and  0.000 
giving  essentially  the  same  form  of  curve  as  for  the  average  of  all  levels. 

The  accelerations  of  rate  are  shown  in  Table  62  and  the  accelerations 
of  specific  rate  in  Table  63  and  in  the  unbroken  line  of  Figure  54.  The 
average  accelerations  of  rate  per  day  are  respectively  -|-0.07S,  0.000, 
— 0.022,  —0.042,  —0.025  and  0.000  mm.  The  average  accelerations  of 
specific  rate  including  all  levels  are  respectively  +0.011,  — 0.001, 
—0.007,  —0.0075,  —0.003  and  0.000  and  including  only  the  four  deepest 
levels,  +0.009,  0.000,  —0.004,  —0.005,  —0.003  and  0.000.  As  for  sec- 
ond regenerations  the  only  plus  acceleration  is  between  2  and  5  days 
and  the  most  rapid  deci-ease  takes  place  between  9  and  11^/4  days. 

The  percentage  increments  per  day  are  shown  in  Table  64  and  in  the 
unbroken  line  of  Figure  55.  The  values  are  respectively  98,  29,  17,  6, 
1  and  0  percent  per  day  giving  approximately  the  same  form  of  curve 
as  for  second  regenerations. 

In  general  the  first  regenerations  agree  with  the  second  but  on  the 
whole  the  second  regenerations  reach  their  maximum  earlier  and  are 
more  rapid  than  the  first  up  to  the  time  of  maximum  rate.  The  first 
are  more  rapid  than  the  second  after  the  maximum. 


119] 


RATE  OF  RECESERATIOX—ZELESY 


119 


2  0      7     9     llli      13  ■* 

— >■      Days  after  the  operation 
Figure  56      Rates  of  first  regenerations  of  the  tail  per  day  at  different  times 
after  the  operation  for  six  different  levels       Ranci  damitans     T^'ie  removed 
lengths  are  1.5,  2.6,  4.6,  8.2,  13.0  and  16.7  mm. 


120 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[120 


TABLE   60 

Rana  clamitans       Series   3676-3765       First  regenerations 

Rate  of  regeneration  of  tail  per  day  at  different  times  during  the  regenerative 

process  for  six  different  levels 


Percent  of 

tail  length 

removed 

6 

10 

17 

30 

48 

62 

Length 

removed  in 

mm. 

1.5 

2.6 

4.6 

8.2 

13.0 

16.7 

No.  of 
individuals 

2 

5 

3 

8 

5 

5 

Days 
0-  4 

0.07 

0.02 

0.12 

0.10 

0.12 

0.12 

4-  6 

0.10 

0.20* 

0.25* 

0.35* 

0.55* 

0.55 

6-  8 

0.15* 

0.10 

0.25* 

0.30 

0.50 

0.70 

S-10 

0.05 

0.15 

0.10 

0.30 

0.40 

0.75* 

1 
10-121/2 

0.00 



0.00 

0.08 

0.04 

0.12 

0.36 

0.52 

121/2-18 

—0.02 

0.00 

0.02 

0.15 

0.18 

18-56 

-0.01 

0.00 

—0.01 

—0.01 

0.00 

0.00 

121] 


RATE   OF  REGEXERATION  —  ZELENY 


121 


TABLE   61. 

Rana  clamitans       Series  3676-3765 

Specific  rates  at  different  levels 


Second  regenerations 
at  different  times 


Percent  of 
tail  length 
removed 

0 

10 

17 

30 

48 

62 

16.7 

5 

Average 

of 

all 

levels 

Average 
of  four 
longest 
remov- 

Length 
removed 
in  mm. 

1.5 

2.6 

4.6 

8.2 

13.0 

No.  of  in- 
dividuals 

2 

5 

3 

8 

5 

Days 
0-  4 

0.042 

0.015 

0.027 

0.012 

0.007 

0.007 

0.018 

0.013 

4-  6 

0.065 

0.040 

0.055* 

0.040* 

0.045* 

0.030 

0.046 
0.057* 

0.042 

6-  8 

0.115* 

0.045 

0.055* 

0.040* 

0.040 

0.045* 

0.045* 

8-10 

0.025 

0.055* 

0.020 

0.035 

0.045* 

0.045* 

0.037 

0.036 

10-121/2 

0.015 

0.040 
—0.007 

0.010 

0.015 

0.035 

0.040 

0.026 

0.002 

—0.001 

0.025 

121/2-18 

—0.002 

0.000 

0.004 

0.011 

0.009 

0.006 

18-56 

—0.004 

—0.001 

—0.001 

—0.001 

0.000 

0.000 

0.000 

ILLIXOIS    BIOLOGICAL    MOXOCR.-IPHS 


[122 


TABLE   62 

Rana  clamitans       Series  3676-3765       First  regenerations 

Acceleration  of  rate  of  regeneration  of  tail  per  day  at  different  times  during  the 

regenerative  process  for  six  different  levels 


Percent  of 

tail  length 

removed 

6 

10 

17 

30 

48 

62 

Average 

of 

all 

levels 

Length    re- 
moved in 
mm. 

1.5 

2.6 

4.6 

8.2 
8 

13.0 

16.7 

No.  of  in- 
dividuals 

2 

3 

5 

5 

Middle  of 

periods 

Days. 

2-  5 

+  0.01 

+  0.06* 

+  0.04* 

+  0.08* 

+  0.14* 

+0.14* 

+0.078* 

5-  7 

+0.02* 

—0.05* 

0.00 
—0.07* 

—0.02 

—0.02 

+  0.07 

0.000 

7-  9 

—0.05* 

+  0.02 

0.00 

—0.05* 

+  0.02 

—0.022 

9-11% 

—0.02 

—0.03 

—0.02 

—0.07* 

—0.02 

—0.09* 
-0.06 

—0.042* 

Il'4-15i4 

0.00 

-0.02 

—0.01 

—0.02 

—0.04 

-0.025. 

1514-37 

—0.00 

0.00 

—0.00 

—0.00 

0.00 

+  0.00 

—0.000 

H 


123] 


RATE  OF  REGEXERATIOS—ZELESY 


123 


TABLE   63 

Rana  clamitans       Series  3676-3765       First  regenerations 
Acceleration  of  specific  rate  of  regeneration  of  the  tail 


Percent  of 

tail 

length 

removed 

6 

10 

18 

31 

49 

67 

Average 
of     . 
all 
levels 

Average 
of  four 
deepest 
levels 

Length 
removed 
in  mm. 

1.5 

2.8 

4.9 

8.4 

13.1 

18.1 

No.  of  in- 
dividuals 

4 

7 

5 

10 

S 

10 

Days 
2-  5 

f0.007 

-1-0.023* 

f0.009* 

-fO.OlO* 

-fO.Oll* 

-1-0.008* 

-1-0.011* 

4-0.009* 

5-  7 

fO.013* 

—0.019* 

0.000 

—0.002 

-0.002 

-1-0.004 

—0.001 

0.000 

7-  9 

—0.033* 

4-0.008 

—0.015* 

0.000 

—0.004* 

-1-0.001 

-0.007 

—0.004 

9-11% 

—0.013 

—0.012 

—0.004 
—0.002 

-0.009* 

—0.002 

—0.005* 

—0.007* 

—0.005* 

ll%-15y4 

0.000 

—0.008 

—0.002 

—0.003 

-0.004 

—0.003 

—0.003 

15»4-37 

0.000 

0.000 

0.000 

0.000 

0.000 

0.000 

0.000 

0.000 

124 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[124 


TABLE  64 

Rana  clamitans       Series  3676-3765       First  regenerations 

Percentage   increment  of  regenerating  tail   per   day   during   each   time   period 

for  six  different  levels 


Percent   of 

tail    length 

removed 

6 

10 

17 

30 

48 

62 

Average 
of 
all 

Length    re- 
moved in 

1.5 

2.6 

4.6 

8.2 

13.0 

16.7 

mm. 

levels 

No.  of  in- 
dividuals 

2 

5 

3 

8 

3 

5 

Days 
4-  6 

33 

200 

50 

87 

110 

110 

"  98 

6-  8 

30 

20 

25 

27 

31 

44 

29 

8-10 

6 

21 

7 

18 

23 

25 

17 

10-121/2 

0 

8 

2 

5 

9 

12 

6 

121/2-18 

0 

-2 

0 

1 

3 

3 

1 

18-56 

.  —0 

0 

—0  ■ 

—0 

0 

+0 

0 

Experiment  III      Rana  clamitans    .  First  and  second  regenerations 
OP  THE  tail      Series  3628-3675 

For  comparison  with  the  data  of  experiments  I  and  II  it  is  of 
interest  to  note  the  results  obtained  from  this  entirely  different 
series  of  the  same  species  which  was  designed  primarily  for  the 
comparison  of  first  and  second  regenerations.  A  full  description  of  tlie 
experiment  is  given  in  the  section  on  the  effect  of  successive  removal 
upon  the  rate  of  regeneration.  The  data  of  specific  value  for  present 
purposes  are  given  in  Table  65.  Measurements  were  made  only  at  six 
and  at  eight  days  after  the  operation.  Fifty  percent  in  length  of  the 
tail  was  removed  in  both  first  and  second  regenerations.  Twenty-  one 
individuals  are  available  for  first  and  sixteen  for  second  regenerations. 

The  rates  per  day  are  0.52  mm.  for  6  to  8  days  for  first  regener- 
ations as  compared  with  0.50  for  the  same  period  in  Experiment  II  and 
0.62  for  second  regenerations  as  compared  with  0.50  in  Experiment  I. 
The  specific  rate  per  day  for  6  to  8  days  for  first  regenerations  is  0.049 


125] 


RATE   OF  REGEXERATIOX—ZELEXV 


125 


and  for  second  regenerations  0.057  as  compared  with  0.050  for  forty 
eight  percent  removals  in  the  first  regenerations  of  Experiment  II  and 
0.050  for  forty  nine  percent  removals  in  the  second  regenerations  of 
Experiment  I. 

The  percentage  increments  per  day  are  26  for  first  regenerations 
as  compared  with  29  in  Experiment  II  and  28  for  second  regenerations 
as  compared  with  28  in  Experiment  I. 

The  close  agreement  of  these  values  taken  from  a  comparatively 
large  number  of  individuals  strengthens  the  conclusion  as  to  the  validity 
of  the  comparisons  at  different  periods  and  levels  in  experiments  I  and  II. 

TABLE   65 

Rana  clamitans       Series  3628-3765 

First  and  second  regenerations  of  the  tail       Six  and  eight  days 


No.  of 
individ- 
uals 

Total 
length 

Tail 
length 
mm. 

Percent 

of 

length 

re- 
moved 

Length 
moved 

Regen- 
erated 
length 
Six 
days 

Regen- 
erated 
length 
Eight 
days 

Rate 
per 
day 

Spe- 
cific 
rate 

Percent- 
age in- 
crement 

per 

day 

First 
regeneration 

21 
16 

32.7 

21.4 

50 

10.6 
10.9 

2.01 

3.06 

0.52 

0.049 

26 

Second 
regeneration 

33.4 

21.8 

50 

2.18 

3.42 

0.64 

0.057 

28 

Experiment  IV      Amblystoma  punctatum      Tail       Series  4600-5052 

Operations  were  made  at  five  levels  approximating  10,  21,  34,  53  and 
74  per  cent  of  the  original  tail  length.     The  removed  lengths  average 
respectively  1.1,  2.2,  3.7,   5.8  and  S.l  mm.     Measurements  were  made 
2,  4,  6,  8-9,  10-11,  13,  14-15  and  16-17  days  after  the  operation.     The 
rates  per  day  for  each  of  the  levels  at  each  of  the  different  times  are 
given  in  Table  66. 

The  specific  rates  are  shown  in  Table  67.  The  averages  for  all  the 
levels  at  each  of  the  time  periods  are  respectively  0.032  mm.  for  0  to  2 
days,  0.004  for  2  to  4  days,  0.053  for  4  to  6  days,  0.039  for  6  to  8  days, 
0.064  for  8.4  to  10.3  days,  0.043  for  10.3  to  13.0  days,  0.012  for  13.0 
to  15.2  days  and  0.019  for  15.2  to  17.3  days.  As  in  the  case  of  other 
salamander  experiments  the  data  are  more  irregular  than  those  for  the 
frog  tadpoles  because  of  the  susceptibility  of  the  salamander  larvae 
to  factors  which  have  not  so  far  been  brought  under  control.  The 
character  of  the  food  is  probably  an  important  factor.  The  greatest 
rate  comes  between  8.4  and  10.3  days  after  the  operation  for  three  of 
the  five  levels  and  also  for  the  average  of  all  levels.    This  is  later  than 


126 


ILLIXOIS   BIOLOGICAL    MONOGRAPHS 


[126 


the  maxiimini  for  the  frog  tadpole  which  comes  between  four  and  six 
days  for  second  regenerations  and  between  six  and  eight  days  for 
first  regenerations.  The  period  of  decline  in  rate  is  also  more  extended 
in  these  salamander  larvae  than  in  the  frog  tadpoles  of  Expei'imeuts 
I  and  II. 

On  account  of  the  irregularity  of  the  data  it  is  not  possible  to 
study  the  acceleration  of  rate  for  the  present  data. 

The  percentage  increments  per  day  are  given  in  Table  68.  The 
values  for  the  seven  time  periods  are  respectively  8,  71,  20,  23,  14,  4 
and  7.  The  greatest  percentage  increment  comes  between  4  and  6 
days  as  in  the  case  of  the  frog  tadpoles.  An  earlier  period,  that  be- 
tween two  and  four  days  is  represented  here.  During  this  period 
the  percentage  increment  is  low.  If  this  value  can  be  accepted  the 
curve  here  includes  the  very  steep  ascending  portion  discussed  above. 
The  irregularities  in  rate  to  which  the  salamander  larvae  are  subject 
and  the  fact  that  the  low  value  during  this  period  does  not  ajspear  in 
all  the  salamander  experiments  however  makes  the  interpretation 
doubtful. 

TABLE   66 
Amblystoma  punctatum  Series  4600-5052 

Rate  of  regeneration  of  tail  per  day  at  different  times  during  the  regenerative 
process   for   five  different   levels 


Percent  of  tail 
removed 

10 

21 

34 

53 

74 

Length  removed, 
in  mm. 

1.1 

2.2 

3.7 

5.8 

8.1 

Days 
0-2 

0.05 

0.07 

0.07 

0.23 

0.26 

2-4 

0.01 

0.00 

0.07 

—0.03 

—0.06 

4-6 

0.10* 

0.16 

0.16 

0.14 

0.27 

6-8.4 

0.03 

0.07 

0.07 

0.29 

0.21 

8.4-10.3 

0.05 

—0.01 

0.39* 

0.43 

0.37 

10.3-13.0 

0.10* 

0.11 

0.07 

0.07 

0.51* 

13.0-15.2 

0.01 

0.17* 

—0.17 

0.18 

0.09 

15.2-17.3 

—0.05 

0.05 

0.11 

0.48* 

0.41 

127] 


RATE   OF  REGENERATION— ZELENY 


127 


TABLE  67 

Amblystoma  punctatum         Series  4600-5052 

Specific  rates  of  regeneration  of  the  tail  at  different  levels  at  different  times 

after  the  operation 


Percent  of  tail 
removed 

10 

21 

34 

53 

5.8 

74 

Average 
of  all 
levels 

Length   re- 
moved in  mm. 

1.1 

2.2 

3.7 

8.1 

Days 
0-2 

0.035 

0.035 

0.020 

0.040 

0.030 

0.032 

2-4 

0.020 

—0.005 

0.015 

—0.005 

—0.005 

0.004 

4-6 

0.095 

0.070 

0.045 

0.025 

0.030 

0.053 

6-8.4 

0.054 

0.033 

0.029 

0.046 

0.033 

0.039 

8.4-10.3 

0.100* 

—0.011 

0.105* 

0.095* 

0.042 

0.064* 

10.3-13.0 

0.044 

0.063 

0.019 

0.011 

0.078* 

0.043 

13.0-13.2 

—0.032 

0.081* 

—0.036 

0.018 
0.0G9 

0.027 

0.012 

15.2-17.3 

0.000 

0.005 

0  005 

0.014 

0.019 

128 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[128 


TABLE   68 

Amblystoma  punctatum         Series  4600-5052 

Percentage  increment  of  regenerating  tail  per  day  during  each  time  period  for 

five  different  levels 


Percent  of  tail 
removed 

10 

21 

34 
3.7 

53 

74 

Average 
of  all 
.levels 

Length    re- 
moved in  mm. 

1.1 

2.2 

5.8 

8.1 

Days 
2-4 

10 

0 

50 

—6 

—12 

8 

4-6 

83* 
10 

107* 

53* 

35 

77* 

71* 

6-8.4 

16 

12 

42* 

20 

20 

S. 4-10.3 

13 

— 2 

49 

31 

24 

23 

10.3-13.0 

27 

17 

5 

3 

23 

14 

13.0-15.2 

1 

—6 

19 

—10 

8 

3 

4 

15.2-17.3 

4 

8 

17 

11 

7 

Experiment  V      Amblystoma  punctatum       Tail      Series  4101-4540 

The  experiment  consists  of  the  regenerations  of  removed  halves  of  the 
tail  without  additional  injury  in  some  individuals  and  with  an  additional 
removal  of  tlie  two  forelegs  in  others.  Measurements  were  made  at  nine 
periods,  2,  4,  6,  8, 10,  12, 14, 16  and  19  days  after  the  operation.  The  rates 
of  regeneration  are  given  in  Table  69.  The  number  of  individuals  for  most 
of  the  levels  is  five.  The  full  data  are  discussed  in  the  section  on  the 
effect  of  degree  of  injury.  The  average  rate  for  each  of  the  different 
times  shows  that  the  maximum  comes  during  the  eight  to  ten  day  period. 
The  high  value  for  the  greater  degree  of  injury  at  14  to  16  days  is 
due  to  the  death  during  that  period  of  the  two  individuals  with  the 
lowest  values.  The  result  agrees  very  well  with  the  maximum  rate  in 
Experiment  IV. 

The  percentage  increments  are  given  in  Table  70.  The  highest 
value  comes  during  the  two  to  four  day  period  followed  by  decrease 
with  but  little  irregularity. 


129] 


RATE  OF  REGENERATION— ZELENY 


129 


Experiment  VI     Amblystoma  punctatum     Tail     Series  3962-4004 

First,  second  and  third  regenerations  after  removal  of  approximately 
one-half  of  the  tail  were  studied.  The  complete  data  are  given  in  the 
section  on  the  effect  of  successive  removals.  Measurements  were  made  at 
2,  4,  6,  8,  10  and  14  days.  The  rates  per  day  are  given  in  Table  71.  The 
maximum  rate  comes  between  8  and  10  days  agreeing  with  the  other  data 
for  regeneration  of  the  tail  in  salamander  larvae. 

The  percentage  increments  are  given  in  Table  72.  The  highest 
rate  comes  at  tlie  earliest  period,  between  two  and  four  days,  and  is 
followed  by  a  rapid  and  then  a  slower  decrease. 


TABLE  69 

Amblystoma  punctatum      Series  4101-4540 

Rate  of  regeneration  per  day  of  tail  at  different  times  during  the  regenerative 

process  for  two  degrees  of  injury 


Period 

of 

regeneration 

Days 

Middle  of 

period 
Days  after 
operation 

Rate  of  regeneration  per 
day  for  each  period 

Average 
rate 

One-half 
tail 

One-half 

tail  + 

fore-legs 

0-2 

1 

0.17 

0.13 

0.15 

2-4 

3 

0.19 

0.27 

0.23 

4-6 

5 

0.29 

0.25 

0.27 

6-8 

7 

0.37 

0.47 

0.42 

8-10 

9 

0.69* 

0.50 

0.59* 

10-12 

11 

0.46 

0.46 

0.46 

12-14 

13 

0.23 

0.37 

0.30 

14-16 

15 

0.37 

0.53* 

0.45 

16-19 

17% 

0.16 

0.03 

0.09 

130 


ILLIXOIS  BIOLOGICAL   MONOGRAPHS 


[130 


TABLE  70 

Amblystoma  punctatum  Series  4101-4540 

Percentage  increment  per  day  of  regenerating  tail  at  different  times  during  the 

regenerative  process  for  two  degrees  of  injury 


Days 


2  to 

4 

4  to 

6 

6  to 

8 

8  to 

10 

10  to 

12 

12  to 

14 

14  to 

16 

Percentage   increment   per 
day  during  each  period 


One-half  tail 


One-half  tail-|- 
fore-legs 


Average 


TABLE  71 

Amblystoma  punctatum      Series  4101-4540 

Rate  of  regeneration  per  day  at  different  times  during  the  regenerative  process 


Period 

of 

regeneration 

Days 

Middle 
of  period 
Days  after 
operation 

Rate  of  regeneration  per  day 
during  each  period 

Average 

First 

Second 

Third 

0-2 

1 

0.11 

0.12 

0.13 

0.12 

2-4 

3 

0.22 

0.25 

0.37 

0.28 

4-6 

5 

0.35 

0.32 

0.18 

0.28 

6-8 

7 

0.41 

0.64* 

0.66 

0.57 

8-10 

9 

0.68* 

0.57 

0.76* 

0.67* 

10-14 

12 

0.45 

0.57 

0.47 

0.50 

131] 


RATE   OF  REGEXERATIOX—ZELEXY 


131 


TABLE  72 

Amblystoma  punctatum     Series  3962-4004 

Percentage  increment  per  day  at  different  times  during  the  regenerative  process 


Days 

Percentage  increment  per  day  during 
each  period 

Average 

First 

Second 

Third 

2  to  4 

100 

100 

142 

114* 

4  to  6 

53 

43 

18 

38 

6  to  8 

30 

45 

48 

41 

8  to  10 

31 

21 

28 

27 

10  to  14 

12 

15 

11 

13 

Experiment  VII 


Amblystoma  punctatum 
Series  4101-4540 


Forelegs 


The  experiment  consists  of  the  study  of  the  rate  of  regeneration 
of  single  completelj'  removed  fore-legs  under  three  degrees  of  injury 
to  the  individual:  without  additional  injury,  with  the  other  fore-leg  re- 
moved at  the  same  time  and  with  the  other  fore-leg  plus  one-half  of  the 
tail  removed  .  Measurements  were  made  at  2,  4,  6,  8,  10,  12,  14,  16  and 
19  days.  The  rates  of  regeneration  are  given  in  Table  73.  The  maxi- 
mum rate  does  not  come  until  the  14  to  16  period.  The  percentage 
increments  are  given  in  Table  74.  The  highest  value  comes  during  the 
2  to  4  day  period.    There  is  a  gradual  decrease  from  this  time. 

On   the  whole  the   data   for  the  leg  regeneration  show  a  more 
extended  period  tlian  do  the  tail  regenerations. 


132 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 


[132 


TABLE  73 
Amblystoma  punctatum      Series  4101-4540 
Rate  of  regeneration  per  day  of  fore-leg  at  different  times  during  the  regener- 
ative  process   for   three   degrees   of   injury 


Period 

of 

regeneration 

Days 

Middle 

of 

period 

bays  after 

operation 

Rate  of  regeneration  per  day 
for  each  period 

Average 

One 
fore-leg 

Both 
fore-legs 

Both  fore- 
legs + 
one-half  tail 

0-2 

1 

0.06 

0.08 

0.07 

0.07 

2-4 

3 

0.04 

0.10 

0.07 

0.07 

4-6 

5 

0.10 

0.08 

0.13 

0.10 

6-8 

7 

0.12 

0.15 

0.09 

0.12 

8-10 

9 

0.12 

0.25 

0.25 

0.21 

10-12 

11 

0.28 

0.18 

0.18 

0.21 

12-14 

13 

0.25 

0.29 

0.34 

0.29 

14-16 

15 

0.52* 

0.41* 

0.39* 

0.44* 

16-19 

17  Va 

0.27 

0.21 

0.27 

0.25 

133] 


RATE  OF  RECEXERATIOS  —  ZELENY 


133 


TABLE   74 

Amblystoma  punctatum      Series  4101-4540 

Percentage  increment  per  day  of  regenerating  fore-leg  at  different  periods  for 

three  degrees  of  injury 


Days 

Percentage  increment  per  day 
during  each  period 

Average 

One 

fore-leg 

Two 

fore-legs 

Both  fore- 
legs + 
one-half 
tail 

2-4 

34 

62* 

46* 

47* 

4-6 

45* 

23 

45 

38 

6-8 

28 

28 

16 

24 

8-10 

19 

30 

35 

28 

10-12 

31 

9 

15 

18 

12-14 

17 

18 

21 

19 

14-16 

26 

19 

17 

21 

16-19 

14 

10 

13 

12 

Discussion 

The  results  obtained  from  the  present  study  show  that  with  certain 
material  it  is  passible  to  control  disturbing  factors  so  as  to  get  data  of 
a  sufficiently  uniform  nature  for  an  analysis  of  the  change  in  rate.  Such 
material  was  found  in  the  tails  of  the  tadpoles  of  Bana  clamitans.  The 
analysis  has  yielded  results  which  should  be  of  value  in  a  determination 
of  the  factors  involved  in  the  stimulation  of  growth  and  more  particu- 
larly those  concerned  in  slowing  it  down  and  finally  bringing  it  to  a  stop. 
The  characteristics  of  the  change  in  rate  have  been  studied  by  means  of 
the  curves  of  rate,  of  acceleration  of  rate  and  of  percentage  increments. 
Tlie  rate  is  slow  at  first,  increases  rapidly  until  it  is  near  a  maximum  at 
about  eight  days ;  then  decreases,  at  first  rapidl.y  and  then  more  and 
more  slowlj-  as  zero  is  approached.  The  acceleration  of  rate  is  plus  only 
between  the  first  two  periods,  i.  e.,  up  to  the  fifth  day.  After  that  it  is 
minus,  reaching  its  lowest  point  at  ten  days.    The  percentage  increment 


134  ILLINOIS  BIOLOGICAL   MONOGRAPHS  [134 

is  very  high  between  the  first  and  second  periods  but  decreases  very 
rapidlj'  at  first  and  then  more  slowly. 

It  is  evident  that  there  is  a  close  similarity  between  the  change  in 
rate  of  growtli  during  the  regeneration  cycle  and  the  change  in  rate 
during  an  ordinary  developmental  cycle  and  thei'e  is  every  I'eason  to 
believe  tliat  tlie  factors  controlling  the  one  are  similar  to  those  controlling 
the  other.  The  problem  of  the  factors  is  particularly  interesting  when 
it  is  noted  that  for  widely  different  levels  the  rates  of  regeneration  differ 
in  such  a  way  that  length  regenerated  in  a  given  time  is  proportional  to 
the  length  removed.  The  process  of  regeneration  apparently  is  initiated 
in  a  similar  manner  at  each  level  but  is  kept  under  such  control  that  only 
a  certain  per  cent  of  the  length  is  regenerated  in  a  given  time. 

Knowledge  of  the  process  is  at  present  insufficient  to  enable  one 
to  discuss  with  profit  the  nature  of  the  control  of  rate  of  regeneration. 
All  that  can  be  done  is  to  point  out  the  relations  of  certain  phenomena. 
The  initial  slow  period  is  coincident  with  the  period  of  cell  migration 
without  cell  division,  the  period  of  rapidly  increasing  rate  is  coincident 
with  the  period  of  rapid  cell  multiplication  without  pronounced  cell 
differentiation  and  the  period  of  rapidly  decreasing  rate  is  associated 
with  the  appearance  of  pronounced  differentiation  in  the  cells.  There  is 
certainly  some  causal  relation  between  these  phenomena. 

SuMM.UtY 

1.  In  second  regenerations  of  the  tail  in  Rana  clamitans  the  average 
specific  rates  are  0.019  mm.  for  the  0  to  4  day  period,  0.066  for  the  4  to  6 
day  period,  0.051  for  6  to  8  days,  0.033  for  8  to  10  days,  0.017  for  10 
to  121/2  days,  0.001  for  I21/2  to  18  days  and  —0.001  for  18  to  56  days. 

2.  Tlie  average  accelerations  of  rate  are  -|-0.095  mm.  per  day  from 
the  first  to  the  second  period,  — 0.015  from  the  second  to  the  third, 
—0.030  from  the  third  to  the  fourth,  —0.058  from  the  fourth  to  the  fifth, 
—0.028  from  the  fifth  to  the  sixth  and  —0.001  from  the  sixth  to  the 
seventh. 

3.  The  average  percentage  increments  between  the  same  periods 
are  respectively  106,  28,  12,  5,  0  and  0. 

4.  The  average  accelerations  of  specific  rate  for  the  four  deepest 
levels  between  the  same  periods  are  respectively  +0.011  mm.,  0.000, 
—0.005,  —0.006,  —0.004  and  0.000. 

5.  In  first  regenerations  of  the  tail  in  Rana  clamitans  the  average 
specific  rates  are  0.018  mm.  for  0  to  4  days,  0.046  for  4  to  6  days,  0.057 
for  6  to  8  days,  0.037  for  8  to  10  days,  0.026  for  10  to  1214  days,  0.002 
for  121/2  to  18  days  and  —0.001  for  18  to  56  days. 

6.  The  average  accelerations  of  rate  are  +0.07S  mm.  per  day  from 


135]  RATE   OF  REGESERATIOX —ZELESY  135 

the  first  to  the  second  period,  0.000  from  the  second  to  the  third,  — 0.022 
from  the  third  to  the  fourth,  —0.042  from  the  fourth  to  the  fifth,  —0.025 
from  the  fifth  to  the  sixth  and  0.000  from  the  sixth  to  the  seventh. 

7.  The  average  accelerations  of  specific  rate  for  the  four  deepest 
levels  between  the  same  periods  are  respectively  +0.009,  0.000,  — 0.004, 
—0.005,  —0.003  and  0.000. 

8.  The  average  percentage  increments  between  the  same  periods  are 
respectively  98,  29,  17,  6,  1  and  0. 

9.  The  experiments  on  salamander  larvae  show  a  similar  change  iu 
rate  of  regeneration  during  the  process  but  the  number  of  individuals 
is  too  small  to  allow  an  analysis  of  the  data. 

10.  The  changes  in  rate  that  have  been  noted  bear  a  definite  relation 
to  the  histological  changes  that  have  been  observed  during  the  regener- 
ation of  the  tail. 


136  ILLINOIS   BIOLOGICAL   MONOGRAPHS  [136 


PART  V 

THE  EFFECT  OF  DEGREE  OF  INJURY  UPON  THE  RATE  OF 
REGENERATION 

In  a  former  series  of  papers  the  writer  gave  the  results  of  experi- 
ments on  the  effect  of  degree  of  injury  upon  the  rate  of  regeneration.  A 
number  of  different  species  of  animals  and  various  combinations  of 
injuries  were  involved.  The  results  then  obtained  tend  on  the  whole 
to  show  that  within  certain  limits  the  rate  of  regeneration  from  an 
injured  surface  is  not  retarded  by  simultaneous  regeneration  in  other 
parts  of  the  body.  Where  a  difference  exists  between  the  rates  with  and 
without  additional  injury  there  is  usually  an  advantage  in  favor  of  the 
part  with  additional  injurj'.  The  differences  are  however  often  slight 
and  in  some  of  the  cases  come  within  tlie  limits  of  probable  error.  It 
is  only  when  the  data  as  a  whole  are  taken  that  it  is  possible  to  judge 
of  the  correctness  of  the  general  conclusion  that  within  fairly  wide  limits 
of  additional  injury  there  is  certainly  no  decrease  in  rate  of  regener- 
ation but  rather  a  tendency  toward  an  increase. 

Some  additional  data  on  these  points  have  been  obtained  in  connec- 
tion with  the  present  study  of  the  factors  of  regeneration.  On  the  whole 
they  confirm  the  previous  results.  The  principal  experiment  (Experi- 
ment I)  was  planned  with  a  view  to  further  analysis  of  the  problem, 
especially  the  determination  of  the  effect  of  additional  injury  to  a  like 
organ  as  compared  with  additional  injury  to  an  unlike  organ. 

Experiment  I      Amblystoma  punctatum      Series  4101-4540 

The  young  were  hatched  on  March  29-April  4,  1913,  and  the  oper- 
ations were  made  on  May  4  and  5.  The  measurements  of  the  control 
individuals  at  the  time  of  the  operations  are  given  in  Table  75.  The 
average  total  length  is  31.3  mm.,  the  tail  length  14.4  mm.,  the  average 
length  of  the  fore-legs  3.6  mm.  and  the  average  of  the  hind-legs  1.5  mm. 

The  measurements  of  control  individuals  at  the  end  of  the  experi- 
ment on  May  23  are  given  in  Table  76.  The  total  average  length  is  42.7 
mm.,  the  tail  length  20.0,  the  average  of  the  fore-legs  6.2  and  the  average 
of  the  hind-legs  4.5  mm. 

The  experiment  consisted  in  the  determination  of  the  regenerated 
length  of  the  right  fore-leg  under  three  degrees  of  injury :  when  the 


137]  RATE   OF  REGEKERATIOX —  ZELEXY  137 

right  fore-leg  alone  is  removed,  when  its  mate  is  also  removed  and  finally 
when  its  mate  and  one-half  of  the  tail  are  removed.  In  the  last  two  eases 
the  average  of  the  two  fore-legs  is  taken  as  the  proper  value  for  the 
regeneration 'of  a  fore-leg.  A  large  number  of  individuals,  all  hatched 
from  the  same  lot  of  eggs,  were  \ised  and  a  selection  of  larvae  was  made 
so  as  to  make  the  experimental  animals  as  nearly  alike  as  possible  in 
this  respect.  In  each  of  the  five  sets  an  individual  for  each  degree  of 
injury  was  kiUed  at  two  days  after  the  operation,  and  also  at  four,  six, 
eight,  ten,  twelve,  fourteen,  sixteen  and  nineteen  days.  The  data  are 
given  in  Tables  77  to  88.  The  three  degrees  of  injury  may  be  represented 
by  (1)  R,  (2)  R-fL,  (3)  R-fL-fi/oT,  in  which  R=right  fore-leg  removed, 
L^eft  fore-leg  removed  and  y2T=one-half  of  the  tail  removed.  The 
second  involves  the  removal  of  some  additional  material  of  the  same 
kind  as  that  removed  in  the  first.  The  third  as  compared  Avith  the  first 
involves  the  removal  of  some  of  the  same  kind  of  material  and  some  of 
another  kind.  In  every  case  it  is  the  regeneration  of  the  fore-leg  that  is 
used  as  the  basis  of  comparison. 

The  additional  simultaneous  injury  and  regeneration  does  not  de- 
crease the  regeneration  of  the  individual  fore-leg.  At  two  days  the 
average  regenerated  lengths  of  a  fore-leg  are  respectively  0.13,  0.16  and 
0.15  mm.  for  the  three  degrees  of  additional  injury;  at  four  days  the 
corresponding  values  are  0.22,  0.36  and  0.29 ;  at  six  days  0.42,  0.53  and 
0.55;  at  eight  days  0.66,  0.83  and  0.73;  at  ten  days  0.91,  1.34  and  1.24; 
at  twelve  days  1.48,  1.60  and  1.61 ;  at  fourteen  days  1.98,  2.19  and  2.29; 
at  sixteen  days  3.02,  3.01  and  3.08 ;  at  nineteen  days  3.84,  3.64  and  3.90. 
At  only  two  of  the  nine  periods  is  the  regeneration  of  the  fore-leg  witliout 
additional  injury  as  rapid  as  that  of  a  fore-leg  with  additional  injury 
and  at  these  two  times  it  is  less  rapid  than  one  of  tlie  two  other  groups. 
In  seven  of  the  nine  cases  the  regeneration  of  the  fore-leg  witliout 
additional  injury  is  less  than  either  of  the  two  with  such  injury. 

Among  the  fortj'  individual  comparisons  in  which  all  three  degrees 
are  present  the  degree  with  no  additional  injury  has  6%  firsts,  the  degree 
with  an  additional  fore-leg  15%  firsts  and  the  degree  with  an  additional 
fore-leg  plus  one-half  of  the  tail  has  17i/j  firsts.  Among  the  nine  time 
groups  the  degree  with  no  additional  injury  has  IV-j  firsts  and  eacli  of 
the  additional  injury  combinations  has  3%  firsts. 

Taking  up  the  lowest  positions  in  the  three  degrees  in  the  same  way, 
among  the  forty  individual  comparisons  the  degree  with  no  additional 
injury  gives  the  lowest  regeneration  in  2\\i\  cases  while  the  additional 
injury  combinations  each  have  only  9i'-j  lowest  regenerations.  Among 
the  nine  time  groups  the  degree  with  no  additional  injury  has  the  lowest 
value  6  times,  the  one  with  an  additional  removal  of  the  other  fore-leg 


138 


ILLIXOIS   BIOLOGICAL   MOXOGRAPHS 


[138 


21/2  times  while  the  one  with  the  highest  degree  of  injury  gives  tlie  lowest 
regeneration  for  the  fore-leg  only  i/o  times. 

These  comparisons  show  very  clearly  that  the  regeneration  of  a  fore- 
leg is  not  as  rapid  when  the  individual  is  regenerating  no  other  part  at 
the  same  time  as  it  is  when  the  other  fore-leg  is  being  regenerated  at 
the  same  time.  The  additional  removal  of  one-half  of  the  tail  does  not 
seem  to  accelerate  the  regeneration  any  further  because  there  is  no  essen- 
tial difference  between  the  effect  of  an  additional  injury  of  a  fore-leg  and 
an  additional  injury  of  a  fore-leg  plus  one-half  of  the  tail.  It  may  be 
that  the  effect  of  additional  removal  is  confined  to  removal  of  a  similar 
part,  the  tail  removal  in  this  case  involving  a  different  kind  of  organ. 
Or  it  may  be  that  the  accelerating  effect  is  found  only  within  certain 
degrees  of  injury  the  limit  being  exceeding  by  the  highest  of  the 
three  degrees. 


Amblystoma  punctatum      Series  4101-4540 
Experiment  I     Controls  at  beginning  of  experiment 


Date 

Cata- 
log 
number 

Total 

length 

mm. 

Tail 

length 

mm. 

Fore  legs 

Hind  legs 

Right 

Left 

Av'age. 

Right 

Left 

Av'age. 

5/4/13 

4110 

35.0 

16.4 

4.0 

4.0 

4.0 

3.0 

3.1 

3.05 

5/4/13 

4210 

31.8 
28.1 

14.8 

3.6 

3.8 

3.7 

1.4 

1.5 

1.45 

5/4/13 

-4310 

11.9 

3.3 

3.3 

3.3 

1.0 

0.9 

0.95  1 

5/4/13 

4320 

33.8 

15.3 
13.8 

3.3 

3.1 

3.2 

1.1 

1.0 

1.05  J 

5/5/13 

4410 

30.2 

3.6 

3.6 

3.6 

1.0 

1.0 

1.0 

5/.?/13 

4510 

28.7 

14.0 

3.9 

3.8 

3.85 

1.4 

1.2 

1.3 

Average 

31.3 

14.4 

3.6 

1.5 

139] 


RATE   OF  REGEXERATIOX—ZELEXY 


139 


TABLE  76 
Amblystoma  punctatum       Series  4101-4540 
Experiment  I     Controls  at  end  of  experiment 


Date 

Cata- 
log 
number 

Total 

length 

mm. 

Tail 

length 

mm. 

Fore  legs 

Hind  legs 

Right 

Left 

Av'age. 

Right 

Left 

Av'age. 

5/23 

4120 
4130 
4140 

46.7 
44.7 
44.5 

24.3 
21.7 
20.1 

6.1 
6.5 
6.5 

6.1 
6.6 
6.4 

6.1 

6.55 

6.45 

5.0 
5.2 
5.2 

5.0 
5.1 
5.1 

5.0 

5.15 

5.15 

Average 

45.3 

22.0 

6.4 

5.1 

5/23 

4220 
4230 
4240 

43.1 
45.5 
43.7 

20.1 
20.6 
20.4 

6.1 
6.0 
6.0 

6.0 
6.0 
5.5 

6.05 

6.0 

5.75 

4.1 
4.0 
4.0 

4.1 
5.0 
4.4 

4.1 
4.5 
4.2 

Average 

44.1 

20.4 

5.9 

4.3 

5/23 

4330 
4340 

47.2 
41.5 

21.9 
19.5 

7.1 
6.1 

7.2 
6.2 

7.15 
6.15 

5.3 

4.0 

5.2 
4.1 

5.25 
4.05 

Average 

44.3 

20.7 

6.6 

4.6 

5/23 

4420 
4430 
4440 

41.0 
40.5 
40.4 

18.2 
19.4 
18.9 

7.0 
5.6 
6.0 

7.0 
5.6 
6.0 

7.0 
5.6 
6.0 

4.9 
4.0 
4.1 

4.8 
4.1 
4.0 

4.85 
4.05 
4.05 

Average 

40.6 

18.8 

6.2 

4.3 

5/23 

4520 
4530 
4540 

36.5 
40.9 
40.6 

39.3 

16.0 
18.5 
19.1 

5.6 
6.7 
5.0 

5.6 
6.8 
5.0 

5.6 

6.75 

5.0 

4.0 
4.9 
4.0 

4.0 
4.8 
4.0 

4.0 

4.85 

4.0 

Average 

17.9 

5.8 

4.3 

Grand 

average 

42.7 

20.0 

6.2 

4.5 

140 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[140 


TABLE  77 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Two  days 


Catalog 
number 


4101-11-21 
4201-11-21 
4301-11-21 
4401-11-21 
4501-11-21 


Average 


Degree  of  injury 


One 
fore-leg 


0.10 
0.10 
0.10 
0.20 
0.15* 


0.13 


Both 
fore-legs 


0.22 

0.15* 

0.15 

0.17 

0.10 


0.16* 


Both 

fore-legs 

-\-  one-half 

tail 


0.22 

0.11 

0.17* 

0.20 

0.07 


0.15 


TABLE  78 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injur} 

Four  days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

+  one-half 
tail 

4102-12-22 

0.25 

0.25 

0.52 

4202-12-22 

— 

0.52 

0.22 

4302-12-22 

0.15 

0.37* 

0.22 

4402-12-22 

0.40* 

0.30 

0.27 

4502-12-22 

0.10 

— 

0.20 

Average 

0.22 

0.36* 

0.29 

141] 


RATE  OF  REGENERATION— ZELENY 


TABLE  79 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Six  days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

+  one-half 
tail 

4103-13-23 

0.40 

0.20 

0.92* 

4203-13-23 

0.50 

0.87* 

0.52 

4303-13-23 

0.45 

0.65* 

0.42 

4403-13-23 

0.45 

0.60* 

0.47 

4503-13-33 

0.30 

0.35 

0.42* 

Average 

0.42 

0.53 

0.55* 

TABLE  80 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  o£  injury. 

Eight    days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

■\-  one-half 
tail 

4104-14-24 

0.50 

0.75 

0.97* 

4204-14-24 

0.80 

0.80 

0.80 

4304-14-24 

0.85 

0.87* 

0.62 

4404-14-24 

0.43 

0.95* 

0.75 

4504-14-24 

0.70 

0.80* 

0.52 

Average 

0.66 

0.83* 

0.89* 

142 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[142 


TABLE  81 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  tor  different  degrees  of  injury 

Ten    days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

-f  one-half 

tail 

4105-15-25 

0.25 

1.82* 

1.60 

4205-15-25 

0.95 

1.10* 

1.07 

4305-15-25 

1.05 

1.22 

1.32* 

4405-15-25 

1.20 

1.37* 

1.07 

4505-15-25 

1.10 

1.20* 

1.12 

Average 

0.91 

1.34* 

1.24 

TABLE   82 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Twelve   days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

-f  one-half 
tail 

4106-16-26 

1.45 

1.50 

1.77* 

4206-16-26 

1.35 

1.47* 

1.44 

4306-16-26 

1.80* 

1.60 

1.65 

4406-16-26 

1.00 

1.70* 

1.50 

4506-16-26 

1.80* 

1.72 

1.67 

Average 

1.48 

1.60 

1.61* 

143] 


RATE  OF  REGESERATION—ZELENY 


143 


TABLE  83 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Fourteen  daj's 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

+  one-half 
tail 

4107-17-27 

2.60 



2.25 

4207-17-27 

1.70 

1.97 

2.22* 

4307-17-27 

1.45 

1.87 

1.95* 

4407-17-27 

2.25 

2.72 

2.90* 

4507-17-27 

1.90 



2.12 

Average 

1.98 

2.19 

2.29* 

TABLE   84 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Sixteen  days 


Degree  of  injury 

Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

-f  one-half 
tail 

4108-18-28 

2.60 

2.60 

2.70* 

4208-18-28 

2.40 

2.62* 

2.22 

4308-18-28 

2.80 

2.67 

2.85* 

4408-18-28 

3.60 

3.57 

3.65* 

4508-18-28 

3.70 

3.57 

3.97* 

Average 

3.02 

3.01 

3.08* 

144 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 


[144 


TABLE  85 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Nineteen  days 


Degree  of  injury 


Both 

Catalog 

One 

Both 

fore-legs 

number 

fore-leg 

fore-legs 

+  one-half 
tail 

4109-19-29 

4.00* 

3.72 

3.95 

4209-19-29 

3.65 

4.05 

4.25* 

4309-19-29 

3.60 

2.85 

3.60 

4409-19-29 

4.10* 

3.95 

3.80 

Average 

3.84 

3.64 

3.90* 

TABLE  86 

Amblystoma  punctatum      Series  4101-4540 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Summary      Two  to  nineteen  days 


Degree  of  Injury 

Days 

One 
fore-leg 

Both 
fore-legs 

Both 

fore-legs 

-f  one-half 

tail 

2 

0.13 

0.16* 

0.15 

4 

0.22 

0.36* 

0.29 

6 

0.42 

0.53 

0.55* 

8 

0.66 

0.83* 

0.73 

10 

0.91 

1.34* 

1.24 

12 

1.48 

1.60 

1.61* 

14 

1.98 

2.19 

2.29* 

16 

3.02 

3.01 

3.08* 

19 

3.84 

3.64 

3.90* 

Groups  first 
Groups   last 

0 

7 

4 
2 

5 
0 

145] 


RATE  OF  REGENERATION— ZELENY 


145 


TABLE   87 
Amblystoma  punctatum       Series  4101-4540 
Length  of  regenerated   fore-leg  for  different  degrees   of  injury 
Tabulation  of  firsts  for  individual  comparisons 


Injury 

Days 

One 
fore-leg 

Both 
fore-legs 

Both 

fore-legs 

-f  one-half 

tail 

2 

1% 

iy2 

2* 

4 

1 

1 

1 

6 

0 

3* 

2 

8 

Vi 

^Vi* 

1/3 

10 

0 

4* 

1 

12 

2 

2 

1 

14 

0 

0 

3* 

16 

0 

1 

4* 

19 

2 

0 

2 

Total  firsts 

i% 

155/6 

17/3 

Groups  first 

m 

3^ 

3^ 

146 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 

TABLE  88 
Amblystoma  punctatum      Series  4101-4540 
Length  of  regenerated  fore-leg  for  different  degrees  of  injury 
Tabulation  of  lowest  values  for  individual  comparisons 


[146 


Injury 

Days 

One 

fore-leg 

Both 
fore-legs 

Both 

fore-legs 

+  one-half 

tail 

2 

3 

1 

1 

4 

1% 

1% 

1 

6 

3 

1 

1 

8 

2^ 

Yi 

2^ 

10 

4 

0 

1 

12 

3 

1 

1 

14 

3 

0 

0 

16 

V2 

3y2 

1 

19 

1 

2 

1 

Total   lasts 

21'^ 

9^ 

9'/3 

Groups   last 

6 

ZVz 

V2 

Experiment  II  Amblystoma  punctatum  Series  4101-4540 
This  experiment  deals  with  the  same  series  of  individuals  as  Experi- 
ment I.  The  comparison  in  this  case  however  is  one  between  the  regen- 
eration of  the  removed  half  of  the  tail  when  it  alone  is  removed  and  its 
regeneration  when  there  is  an  additional  removal  of  the  two  fore-legs. 
The  data  are  given  in  Tables  89  to  99.  At  two  days  the  regeneration  of 
the  tail  without  an  additional  injury  is  0.35  mm.  and  with  an  additional 
injury  0.27.  The  corresponding  values  at  4  days  are  0.73  and  0.81,  at 
6  days  1.32  and  1.31,  at  8  days  2.06  and  2.26,  at  ten  days  3.44  and  3.27, 
at  twelve  days  4.36  and  4.20,  at  fourteen  days  4.82  and  4.94,  at  sixteen 
days  5.57  and  6.00  and  at  nineteen  days  5.90  and  6.06.  The  regenerating 
tail  with  no  additional  injury  is  ahead  at  four  times  and  the  one  with 
additional  injury  is  ahead  five  times.     In  thirty  three  individual  com- 


147] 


RATE   OF  REGEX ERATION  —  ZELES Y 


147 


parisoQS  the  group  with  no  additional  injury  is  ahead  seventeen  times 
and  the  additional  injury  group  sixteen  times.  Taking  the  individual 
cases  by  time  groups  the  individuals  with  no  additional  injury  are  ahead 
5^2  times  and  those  with  an  additional  injury  31/^  times. 

These  comparisons  show  no  advantage  of  one  combination  over  the 
other.    The  additional  removal  of  the  fore-legs  does  not  retard  nor  does 
it  accelerate  the  regeneration  of  the  tail.     This  result  strengthens  the 
view  that  the  acceleration  in  Experiment  I  is  probably  due  to  the  addi- 
tional removal  of  material  similar  to  that  whose  rate  is  being  studied. 
TABLE   S9 
Amblystoma  punctatum       Series  4101-4540 
Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 
Two  days 


Catalog 
number 


4131-21 
4231-21 
4331-21 
4431-21 
4531-21 

Average 


Degree  of  injury 


One-half 

tail 

-f  fore-legs 


0.15 
0.35 
0.25 
0.30 
0.30* 


0.27 


TABLE  90 

Amblystoma  punctatum      Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Four  days 


Catalog 
number 


Degree  of  injury 


148 


ILLINOIS   BIOLOGICAL   MOXOGRAPHS 


[148 


TABLE  91 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  tor  different  degrees  of  injury 

Six  days 


Degree  of  injury 

Catalog 
number 

One-half 
tail 

One-half 

tail 

+  fore-legs 

4133-23 
4233-23 
4333-23 

4433-23 
4533-23 

1.60 
0.90 
1.70* 
1.10 

1.00* 
1.65 
1.50* 
1.10 

Average 

1.32* 

1.31 

TABLE  92 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Eight    days 


Degree 

3f  Injury 

Catalog 
number 

One-half 
tail 

One-half 

tail 

-\-  fore-legs 

4134-24 
4234-24 
4334-24 
4434-24 
4534-24 

2.40 

1.80 

1.80 

2.70* 

1.60 

2.60* 
1.90* 
2.26* 
2.30 

Average 

2.06 

2.26* 

149] 


RATE  OF  REGESERATION—ZELENY 


149 


TABLE  93 

Amblystoma  punctatum       Series  4101-4540 

Lengtli  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Ten  days 


Degree 

of  injury 

Catalog 

One-balf 

One-half 

number 

tail 

tail 
-f  fore-legs 

4135-25 

3.65* 

3.20 

4235-25 

2.55 

4335-25 

3.20 

1.46 

4435-25 

3.65* 

3.20 

4535-25 

3.25 

4.15* 

Average       | 

3.44* 

3.27 

TABLE  94 

Amblystoma  punctatum       Series  4101-4540 

Lengtli  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Twelve  days 


Catalog 
number 


4136-26 
4236-26 
4336-26 
4436-26 
4536-26 

Average 


Degree  of  injury 


One-half 
tail 
fore-legs 


150 


ILLIXOIS  BIOLOGICAL   MOXOGRAPHS 


[ISO 


TABLE  95 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Fourteen  days 


Degree  of  injury 

Catalog 
number 

One-half 
tail 

One-half 

tail 

+  fore-legs 

4137-27 
4237-27 
4337-27 
4437-27 
4537-27 

4.80 

4.90* 

5.00* 

4.90* 

4.50 

6.00* 

4.70 

4.95 

4.00 

5.05* 

Average 

4.82 

4.94* 

TABLE  96 

Amblystoma  punctatum       Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  Injury 

Sixteen  days 


Degree  of   injury 

Catalog 
number 

One-half 
tail 

One-half 

tail 

-j-  fore-legs 

4138-28 
4238-28 
4338-28 
4438-28 
4538-28 

6.50* 

5.80 

5.00 

5.00 

8.00 

5.50 

6.40* 

6.10 

Average 

5.57 

6.00* 

151] 


RATE  OF  RECEXERATIOX  —  ZELENY 


151 


TABLE  97 

Amblystoma  punctatum      Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Nineteen  days 


Degree 

Df  injury 

Catalog 
number 

One-half 
tail 

One-half 
tail 

4139-29 
4239-29 
4339-29 
4439-29 

6.90* 
3.20 

4.90 

5.90 
6.20 
5.55 
6.60* 

Average 

5.90 

6.06* 

TABLE  98 

Amblystoma  punctatum     Series  4101-4540 

Length  of  regenerated  tail  in  millimeters  for  different  degrees  of  injury 

Summary      Two  to  nineteen  days 


Degree 

Df  injury 

Days 

One-half 
tail 

One-half 

tail 
+  fore-legs 

2 

0.35* 

0.27 

4 

0.73 

0.81* 

6 

1.32* 

1.31 

8 

2.06 

2.26* 

10 

3.44* 

3.27 

12 

4.36* 

4.20 

14 

4.82 

4.94* 

16 

5.57 

6.00* 

19 

5.90 

6.06* 

Groups    first 

4 

5 

152 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[152 


TABLE  99 

Amblystoma  punctatum      Series  4101-4540 

Length  of  regenerated  tail  for  different  degrees  of  injury 

Tabulation    of   firsts    for    individual    comparisons 


Injury 

Days 

One-half 

One-half 

tail 

tail 

+  fore-legs 

2 

21/2* 

iy2 

4 

21/2 

21/2 

6 

1 

2* 

8 

1 

3* 

10 

2* 

1 

12 

3* 

2 

14 

3* 

2 

16 

1 

1 

19 

1 

1 

Total  firsts 

17 

16 

Groups   first 

51/2 

314 

Experiment  III      Amblystoma  punctatum       Series  4005-4008 


Experiments  III,  IV,  V  and  VI  comprise  merely  a  few  individual 
comparisons  obtained  from  experiments  devised  principally  for  the 
study  of  other  factors.  They  are  included  here  under  the  rule  that  no 
valid  data  on  the  matter  at  hand  are  to  be  excluded. 

In  Experiment  III  the  regeneration  of  the  hind-leg  is  compared 
under  the  four  conditions  of  (1)  no  additional  injury,  (2)  removal  of 
the  other  hind-leg,  (3)  removal  of  the  other  hind-leg  and  one  fore-leg 
and  (4)  removal  of  the  other  hind-leg  and  both  fore-legs.  The  data 
are  given  in  Table  100. 

Three  sets  of  comparisons  were  made  at  twelve  days  after  the  oper- 
ations, each  with  a  single  individual  for  each  degree  of  injury.  The 
regenerating  hind-leg  with  no  additional  injury  is  distinctly  behind  the 
cases  with  additional  injury.  The  greatest  regenerated  length  comes  in 
one  case  with  an  additional  injury  of  one  hind-leg  plus  one  fore-leg  and 
in  two  cases  with  one  hind-leg  plus  two  fore-legs.    The  averages  begin- 


153] 


RATE   OF  RECESERATIOS  —  ZELENY 


153 


niiig  with  the  lowest  degree  of  injury  are  respectively  1.50,  1.73,  1.86 
and  1.88  mm. 

The  additional  removals  are  in  every  case  removals  of  leg  material 
and  the  result  agrees  with  that  of  experiment  I  in  giving  an  increased 
rate  of  regeneration  of  a  part  when  similar  organs  are  removed  at  the 
same  time. 

TABLE  100 

Amblystoma  punctatum       Series   4005-4008 

Length  of  regenerated  hind  leg  in  millimeters  for  different  degrees  of  injury 

Twelve   days 


Catalog 
number 

Degree 

of  injury 

One 

hind-leg 

Both 
hind-legs 

Both  hind- 
legs+one 
fore-leg 

Both  hind- 
legs -f  both 
fore-legs 

4005 
4006 
4008 

1.35 
1.65 
1.50 

1.90 
1.80 
1.50 

1.95* 

1.82 

1.80 

1.75 

1.92* 

1.85* 

Average 

1.50 

1.73 

1.86* 

1.84 

TABLE  101 

Amblystoma   punctatum      Series   400.')-4008 

Length  of  regenerated  fore-leg  in  millimeters  for  different  degrees  of  injury 

Twelve   days 


Degree  of  injury 

Catalog 

number 

One 

Both 

fore-leg 

fore-legs 

+  both 

+  both 

hind-legs 

hind-legs 

4005 

3.0* 

2.8 

4006 

3.1* 

3.0 

4008 

3.0 

3.15* 

Average 

3.07* 

2.98 

Experiment  I\'      A.mulystoma  punctatum      Series  4005-4008 

In  this  expeiiiiicnt  tiie  regeneration  of  the  right  fore-leg  is  compared 
under  conditions  of  differing  degrees  of  additional  injury.  In  one  com- 
bination there  is  an  additional  removal  of  the  two  hind  legs  and  in  the 


154 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 


[1S4 


otlier  of  both  hiud-legs  plus  the  remaining  fore-leg.  The  data  are  given 
in  Table  101.  In  two  of  the  three  cases  the  smaller  additional  degree  of 
injury  shows  the  greater  regeneration  of  the  fore-leg.  The  average  is 
3.07  mm.  for  the  lesser  degree  and  2.98  for  the  greater  degree,  an 
advantage  in  favor  of  the  lesser  degree. 

It  should  be  noted  that  this  is  not  strictly  comparable  with  the 
main  issue  of  Experiments  I,  II  and  III.  Aside  from  tlie  small  number 
of  cases  it  is  a  comparison  between  two  degrees  of  injury  each  of  which 
is  of  considerable  extent.  It  may  be  that  the  removal  of  three  of  the 
four  legs  is  near  the  degree  of  injury  yielding  the  maximum  rate  for  each 
removed  leg. 

Experiment  V      Amblystojia  punctatum       Series  4010-4025 

A  comparison  is  made  between  the  regeneration  of  a  half  of  the  tail 
when  it  alone  is  removed  and  when  both  fore-legs  are  removed  at  the 
same  time.  Four  individual  comparisons  are  made  at  fourteen  days. 
The  data  are  given  in  Table  102.  The  regenerated  lengths  and  specific 
lengths  regenerated  are  ahead  in  two  of  the  four  cases  for  each  of  the 
degrees  of  injury.  The  average  regenerated  length  with  no  additional 
injury  is  5.1  mm.  and  with  additional  injury  5.0  mm.  The  specific 
regenerated  length  is  0.65  with  no  additional  injury  and  0.68  with  addi- 


TABLE  102 

Amblystoma  punctatum       Scries  4010-4025 

Regeneration  of  tail  for  different  degrees  of  injury 

Fourteen  days 


Degree 

of  injury 

C 

)ne-half  tai 

Length 
regener- 
ated 

One-half  tail  -|-  both 

fore-legs 

Catalog 
number 

Length 
removed 

Specific 
amt.  re- 
generated 

Length 
removed 

Length 
regener- 
ated 

Specific 
amt.  re- 
generated 

4014-13 

7.7 

4.9 

0.64 

7.0 

5.2* 
4.3 

0.74* 

4018-17 

8.8 

5.2* 

0.59* 

8.0 

0.54 

4022-21 

8.0 

5.3* 

0.66* 

8.0 

5.1 

0.64 

4025-24 

7.0 

4.9 

0.70 

6.6 

5.3* 

0.80* 

Average 

5.1 

0.65 

5.0 

0.68 

155] 


RATE   OF  REGENERATIOX—ZELENY 


155 


tioual  iujurj'.  The  data  show  essential  equality  between  the  rates  of 
regeneration  under  the  two  conditions  of  the  experiment.  This  agrees 
with  the  data  in  Experiments  I  and  II  which  show  no  increase  or  decrease 
in  rate  of  regeneration  when  unlike  material  is  removed  simultaneously 
with  the  removal  of  the  organ  whose  rate  is  being  studied. 

Experiment  VI      Ambltstoma  punctatuii       Series  4010-4025 

Three  individual  comparisons  were  made  at  fourteen  days  of  the 
right  fore-leg,  when  it  alone  is  removed,  when  the  other  fore-leg  is  also 
removed  and  when  the  other  fore-leg  plus  one  half  of  the  tail  is  removed. 
The  data  are  given  in  Table  103.  In  two  of  the  three  cases  the  individuals 


TABLE  103 

Amblystoma  punctatum       Series   4010-4025 

Length  of  regenerated  fore-leg  in  millimeters   for  different  degrees  of  injury 

Fourteen  days 


Degree  of  injury 

Catalog 
number 

One 
fore-leg 

Both 
fore-legs 

Both 

fore-legs 

+  one-half 

tail 

4011,12,13 
4015, 16, 17 
4019,  20,  21 
4023,— ,24 

2.00* 
2.00* 
1.95 
2.00 

1.77 
1.60 
1.82 

1.65 
1.80 
2.22* 
2.00 

Average 

1.99* 

1.73 

1.92 

with  no  additional  regeneration  are  ahead  of  the  others.  The  greater 
injury  gives  the  greater  rate  in  one  of  the  three.  The  average  regener- 
ated lengths  beginning  with  the  lowest  degree  of  injury  are  respectively 
1.99,  1.73  and  1.92  mm.  The  few  cases  may  be  a  sufficient  explanation 
of  the  lack  of  agreement  with  the  more  extended  series  of  Experiment  I. 

Discussion 

The  experiments  as  a  whole  show  that  a  part  regenerates  slightly 
more  rapidly  when  additional  material  of  the  same  kind  is  removed  tlian 
when  the  part  alone  is  removed.  Simultaneous  removal  of  tail  material 
does  not  accelerate  the  regeneration  of  a  leg  nor  does  simultaneous  re- 
moval of  a  leg  accelerate  the  regeneration  of  the  tail.  The  rate  in  these 
eases  however  is  not  decreased  by  the  additional  injurj'.     The  state- 


156  ILLINOIS  BIOLOGICAL   MONOGRAPHS  [156 

ment  may  therefore  be  made  that  within  limits  the  regeneration  of  a  part 
is  not  retarded  by  simultaneous  removal  and  regeneration  of  material  in 
other  parts  of  the  body.  When  this  additional  material  is  of  the  same 
kind  as  that  whose  rate  is  being  studied  there  may  even  be  an  acceler- 
ation of  regeneration. 

In  comparison  with  such  a  factor  as  level  of  the  cut  this  difference 
in  rate  is  slight  and  no  such  quantitative  relation  as  in  that  case  can  be 
made  out.  It  must  however  be  considered  that  the  principal  object  of  the 
original  experiments  was  to  show  that  additional  injury  within  the  given 
limits  tends  to  increase  rather  than  decrease  the  rate  of  regeneration. 
This  has  been  proved  for  these  experiments.  The  evidence  in  favor  of 
a  definite  increase  in  rate  with  any  certain  increase  in  degree  of  injury 
is  not  so  conclusive.  It  is  obvious  that  in  many  series  of  experiments 
factors  whose  influence  is  greater  than  that  of  the  factor  under  discus- 
sion may  obscure  the  result. 

Emphasis  should  again  be  placed  on  the  fact  that  all  data  obtained 
by  the  writer  are  included.  That  some  of  the  series,  especially  those  with 
a  few  individuals,  diverge  from  the  general  result  is  to  be  expected  by 
anyone  in  similar  work  who  has  attempted  to  eliminate  entirely  all  of  the 
factors  except  the  one  under  observation  at  a  particular  time. 

Summary 

1.  A  comparison  was  made  of  the  rate  of  regeneration  of  a  leg  or 
of  the  tail  of  an  Amblystoraa  larva  when  the  part  alone  is  removed 
with  its  rate  when  similar  or  dissimilar  parts  of  the  individual  are 
removed  at  the  same  time.  The  data  are  derived  from  two  principal 
Experiments,  I  and  II,  and  from  a  few  scattered  observations  listed  as 
Experiments  III  to  VI. 

2.  In  Experiment  I  a  comparison  was  made  of  the  rate  of  regener- 
ation of  the  right  fore-leg  when  it  alone  is  removed  witli  its  rate  when 
the  other  fore-leg  is  removed  at  the  same  time  and  when  the  other  fore- 
leg and  one  half  of  the  tail  are  removed.  The  result  obtained  from  forty 
individual  comparisons  made  at  different  times  shows  that  the  rate  of 
regeneration  of  the  right  fore-leg  in  each  of  the  series  with  additional 
injury  is  greater  than  in  the  series  without  additional  injui-y. 

3.  The  rate  of  regeneration  of  a  right  fore-leg  when  its  mate  plus 
one-half  of  the  tail  is  removed  is  not  essentially  different  from  the  rate 
when  its  mate  alone  is  removed.  The  addition  of  the  injury  to  a  dissimilar 
organ,  the  tail,  does  not  alter  the  rate  of  regeneration  of  the  fore-legs. 

4.  In  Experiment  II  it  is  shown  that  there  is  no  significant  differ- 
ence between  the  rate  of  regeneration  of  a  tail  one-half  of  which  has  been 


157]  RATE   OF  REGEXERATIOX  —  ZELEXY  157 

removed  without  additional  injury  to  the  individual  and  the  rate  after 
the  same  injury  plus  a  removal  of  both  fore-legs. 

5.  The  data  of  Experiments  III  to  VI  show  some  departures  from 
the  general  rule  probably  because  they  deal  with  few  individuals.  On 
the  whole  however  they  bear  out  the  results  obtained  from  the  principal 
experiments. 


1S8  ILLINOIS  BIOLOGICAL   MONOGRAPHS  [158 


PART  VI 

THE  COMPLETENESS  OP  REGENERATION 

One  of  tlie  striking  facts  in  connection  with  amphibian  regeneration 
as  made  out  in  the  present  studies  is  the  lack  of  completeness  of  the 
process.  When  a  part  of  the  tail  is  removed  the  lost  part  is  never  com- 
pletely restored.  Data  on  this  problem  are  to  be  found  in  a  number  of 
sets  of  experiments  one  of  which  (Experiment  V)  was  devised  especially 
for  the  present  purpose. 

Experiment  I      Rana  clamitans      Series  3557-3624 

One-half  of  the  tail  was  removed  in  the  individuals  of  three  groups, 
A,  B  and  C.  After  35  to  39  days,  which  was  sufficiently  long  so  that 
regeneration  had  stopped,  another  removal  was  made  and  so  on  until  eaeli 
individual  had  undergone  five  regenerations.  The  data  are  given  in 
Table  104.  The  aA'erage  removed  length  as  estimated  from  the  measure- 
ment of  a  few  individuals  was  17.0  mm.  The  average  length  of  the  com- 
pleted first  regeneration  is  8.6  mm.  or  51  per  cent  of  the  removed  length, 
of  the  second  regeneration  8.0  mm.  or  53  per  cent,  of  the  third  7.5  mm. 
or  51  per  cent,  of  the  fourth  5.5  mm.  or  42  per  cent  and  of  the  fifth 
6.4  mm.  of  45  per  cent.  On  the  average  about  one-half  of  the  removed 
length  is  replaced  when  one-half  of  the  tail  length  is  removed. 

Experiment  II       Rana  clamitans      Series  3628-3675 

One-half  of  the  tail  length  was  removed  in  the  individuals  of  this 
experiment  and  regeneration  was  allowed  to  proceed  for  twenty  days, 
a  sufficient  time  for  bringing  it  to  a  stop.  The  data  are  given  in  Table 
105.  The  average  original  tail  .length  was  21.8  mm.,  of  the  removed 
length  10.6  mm.  and  of  the  regenerated  length  5.4  mm.  The  completed 
regenerated  length  is  thus  51  per  cent  of  the  removed  length. 

Experiment  III       Rana  clamitans      First  regenerations 
Series  3676-3765 

The  data  are  given  in  Table  106.  The  tails  were  removed  at  different 
levels  approximating  6,  10,  17,  30,  48  and  62  per  cent  of  the  tail  lengths. 
Regeneration  was  completed  at  these  levels  at  121/2,  121/^,  12i/^,  IS,  18 


159] 


RATE   OF  REGEXERATIOX—ZELEXV 


159 


and  56  days  respeetivel.y.  The  regenerated  lengths  at  these  times  of 
completion  are  respectively  61,  46,  39,  33,  42  and  41  per  cent  of  the 
removed  lengths.  It  will  be  noted  that  the  two  shortest  removals  give 
the  highest  per  cents  and  the  two  medium  ones  the  lowest  per  cents. 
This  difference  is  discussed  in  Part  III  on  the  effect  of  level  of  the  cut. 

Experiment  IV      Rana  clahitaxs      Second  regenerations 
Series  3676-3765 

The  data  are  given  in  Table  107.  The  tail  was  removed  at  different 
levels  approximating  6,  10,  18,  31,  49  and  67  per  cent  of  the  removed 
lengths.     Regeneration  was  completed  for  these  levels  at  10,  10,  12i/^, 

TABLE   104 

Rana  clamltans       Series  3557-3624       Completeness  of  regeneration 
Successive   regenerations   in    single   individuals       One-half   of   tail   removed  = 
17  mm.  on  the  average       First  operation  Oct.  23.  1911       Second  operation 
Groups  A  and  B  Nov.  18       Group  C  Nov.  28 


Group 
A 


Group 
B 


Catalog 
number 

First 
regener- 
ation 

Nov.  28 

3564 
3565 
3566 
3567 
3568 
3569 
3570 

Average 

3578 
3579 
3580 
3581 
3582 
3583 
3584 

Average 

Second 
regener- 
ation 


Jan.   3 


9.5 

9.8 
10.0 
11.9 

8.4 
10.0 

8.7 

9.8 

8.3 
8.2 
11.9 
9.7 
8.3 


Third 
regener- 
ation 


Feb.  9 


8.5 
11.4 
9.3 
9.5 
9.9 
8.7 
8.1 

9.3 

9.0 
8.1 
7.3 
8.0 
12.8 
7.4 
9.5 

8.9 


Fourth 
regener- 


7.3 

8.1 

8.0 

11.0 

8.0 


8.5 

5.8 
11.3 
6.9 
7.6 
7.4 
5.0 
6.4 

7.2 


Fifth 
regener- 


April  24 


8.2 
6.3 
11.9 
8.5 
8.1 


8.6 

8.2 
7.0 
8.1 
11.6 
5.4 
6.8 


160 


ILLIXOIS   BIOLOGICAL   MONOGRAPHS 


(160 


TABLE  104   (Coutinued) 


First 

Second 

Third 

Fourth 

Fifth 

regener- 

regener- 

regener- 

regener- 

regener- 

Catalog 

ation 

ation 

ation 

ation 

ation 

number 

Nov.  28 

Jan.  3 

Feb.  9 

Mar.  16 

April  24 

3586 

8.1 





— 



3588 

6.1 

7.5 

7.3 

5.7 

7.2 

3590 

8.5 

6.6 

7.5 

5.1 

6.5 

3592 

7.1 

8.0 

5.7 

4.9 

6.5 

3594 

8.6 

7.8 

2.0 

5.0 

6.1 

3596 

9.0 

8.6 

9.4 

6.7 

6.8 

3598 

10.7 

9.7 

9.3 

6.1 

6.2 

3600 

8.2 

8.0 

6.9 

5.8 

5.9 

3602 

9.9 

7.7 

6.8 

4.4 

4.7 

Group 

3604 

9.6 

7.6 

6.C 

4.9 

5.7 

C 

3606 

7.4 

7.8 

8.0 

5.0 

5.9 

3608 

9.0 

8.0 

9.0 

5.5 

6.9 

3610 

8.5 

8.9 

8.3 

5.4 

7.1 

3612 

7.4 

7.0 

7.1 

4.8 

5.5 

3614 

8.3 

6.6 

6.2 

4.5 

5.2 

3616 

8.0 

8.3 

7.9 

6.1 

7.9 

3618 

9.7 

9.5 

9.7 

7.3 

8.0 

3619 

— 

8.0 

7.3 

6.6 

6.1 

3622 

10.2 

8.5 

— 

— 

— 

3624 

9.3 

7.5 

— 

— 

— 

Average 

8.6 

8.0 

7.5 

5.5 

6.4 

Percent 

of   removed 

length     r 

egen.      Av. 

51 

53 

51 

42 

45 

121/2,  56  aiul  56  days  respectively.  The  regenerated  lengths  at  these  times 
of  completion  are  respectively  67,  46,  33,  31,  40  and  39  per  cent  of  the 
removed  lengths.  As  in  the  case  of  the  first  regenerations  the  two  shortest 
removals  give  the  highest  per  cent  of  regeneration  and  the  two  medium 
removals  the  lowest  per  cent. 

Experiment  V      Amblystoma  punctatum       Series  6212-6281 

The  experiments  on  tadpoles  of  Rana  clamitans  having  shown  that 
only  a  half  or  less  of  the  removed  length  on  the  average  is  completed  dur- 
ing regeneration  it  became  a  matter  of  interest  to  see  if  this  might  not 
have  been  due  to  the  age  of  the  tadpoles,  which  were  obtained  in  the  fall. 
Accordingly  a  series  of  Amblystoma  larvae  was  operated  upon  within  a 


161] 


RATE  OF  REGENERATION —ZELENY 


161 


few  days  after  they  had  left  the  egg  envelopes  and  was  kept  until  the 
salamanders  were  weU  advanced  in  their  metamorphosis.  Since  in  young 
salamander  larvae  the  border  line  between  old  and  regenerated  tissue  is 
soon  obliterated  it  became  necessary  to  devise  another  method  of  testing 
completeness  of  regeneration  than  the  direct  measurement  of  the  regen- 

TABLE  105 
Rana  clamitans      Series  3628-3675 


Tail 

Removed 

length 

length 

24.1 

13.1 

24.6 

13.2 

22.1 

11.0 

23.2 

11.1 

23.1 

11.7 

25.0 

12.5 

20.4 

9.9 

20.8 

10.0 

29.2 

15.5 

23.8 

10.5 

23.3 

10.9 

25.6 

10.9 

20.8 

10.1 

19.2 

9.8 

21.1 

11.5 

22.0 

11.8 

17.0 

8.2 

19.0 

9.7 

22.4 

9.8 

19.8 

10.1 

20.8 

8.4 

21.8 

9.1 

15.4 

7.3 

18.1 

9.0 

21.8 

10.6 

Percent 

removed 

49 

Regenerated 

length 

Twenty 

days 


5.9 
5.2 
4.9 
5.5 
5.9 
5.8 
5.6 
5.2 
5.9 
5.6 
5.6 
5.9 
4.7 
4.6 
5.5 
6.1 
5.6 
5.5 
4.3 
5.2 
5.1 
5.0 
6.0 
6.0 


Percent    of    removed 
part  regenerated 


162 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


[162 


TABLE  106 
Rana   clamitans       Series    3676-3765      First    regenerations 


Average 

Percent 

Tail 

maximum 

Average 

Days  after 

Number 

of  tail 

length 

regeneration 

maximum 

operation 

of 

length 

removed 

in 

regeneration 

when  maxi- 

cases 

r  emoved 

in  mm. 

percent  of 

in  mm. 

mum  is 

Average 

Average 

removed 
length 

reached 
Average 

2 

6 

10 

1.5 

61 

0.9 

12y2 

5 

2.6 

46 

1.2 

12  Va 

3 

17 

4.6 

39 

1.8 

12  Vo 

8 

30 

8.2 

33 

2.7 

18 

5 

48 

13.0 

42 

5.5 

18 

5 

62 

16.7 

41 

6.9 

56 

TABLE  107 
Rana  clamitans     Series  3676-3765     Second  regenerations 


Average 

Percent 

Tail 

maximum 

Average 

Days  after 

Number 

of  tail 

length 

regeneration 

maximum 

operation 

of 

length 

removed 

in 

regeneration 

when  maxi- 

cases 

removed 

in  mm. 

percent  of 

in  mm. 

mum  is 

Average 

Average 

removed 

reached 

length 

Average 

4 

6 

1.5 

67 

1.0 

10 

7 

10 

2.8 

46 

1.3 

10 

5 

18 

4.9 

33 

1.6 

12  Vs 

10 

31 

8.4 

31 

2.6 

121/2 

8 

49 

13.1 

40 

5.2 

56 

10 

67 

18.1 

39 

7.1 

56 

163]  RATE   OF  REGEXERATIOX —ZELEKY  163 

erated  material.  This  consisted  iu  a  comparison  of  the  ratio  between  tail 
length  and  body  length  in  the  operated  individuals  with  that  in  control 
iinoperated  individuals.     This  was   done   after  regeneration   had   been 

tail 
going  on  during  the  whole  larval  period.    If  tlie    — —  period  is  the  same 

in  operated  as  in  unoperated  individuals  it  is  proper  to  suppose  that 
regeneration  has  been  complete.  If  however  the  ratio  is  lower  the 
conclusion  that  regeneration  is  incomplete  is  very  probably  correct 
though  absolute  certainty  can  not  be  assumed  because  of  the  possibility 
of  the  changed  ratio  being  due  to  regulatory  changes  in  other  parts  of  the 
indi\adual. 

The  experiment  consists  of  a  comparison  of  the  relative  degree  of 
completeness  of  regeneration  of  the  tail  in  four  groups,  (1)  with  no 
operation,  (2)  with  one-fourth  of  the  tail  removed,  (3)  with  one-half 
of  the  tail  removed  and  (4)  with  three-fourths  removed.  The  operations 
■were  made  as  soon  as  possible  after  the  animals  left  the  egg  envelopes 
and  the  experiment  proceeded  until  all  four  legs  were  well  developed 
and  absorption  of  the  gills  had  begun.  This  allowed  practically  the  entire 
larval  period  for  regeneration.  There  were  seventy  individuals  at  the 
start  but  a  high  mortality  reduced  the  number  very  considerably.  Lim- 
nodrilus  was  used  as  food. 

The  data  are  given  in  Tables  108  to  112.  The  average  ratio  between 
tail  and  body  length  in  control  individuals  at  the  end  of  the  experiment 
is  1.09,  in  indi\-iduals  with  one-fourth  of  the  tail  removed  it  is  1.01,  in 
those  with  one-half  removed  0.93  and  with  three-fourths  removed  0.S6. 
This  progressive  relative  decrease  iu  the  tail  length  as  compared  with  the 
body  length  is  very  probably  due  to  lack  of  completeness  of  regeneration 
even  though  the  whole  larval  period  has  been  allowed  for  such  completion. 

Discussion 

Apart  from  the  starting  stimulus  in  regeneration  the  most  interesting 
problem  is  undoubtedly  that  of  the  stopping  stimulus.  With  the  growth 
once  started  what  are  the  factors  involved  in  checking  it?  In  general  it 
has  been  assumed  that  regeneration  goes  on  until  the  removed  organ  is 
entirely  replaced  and  that  over-  and  under-regeneration  occur  but  rarely. 
The  present  data  make  it  probable  that  incompleteness  is  more  general 
than  has  been  supposed.  The  factors  at  work  iu  bringing  regeneration 
to  a  close  tend  to  overdo  rather  than  underdo  their  function. 

A  further  investigation  of  the  problem  of  completeness  of  regener- 
ation would  be  of  interest. 


164 


ILLINOIS  BIOLOGICAL   MONOGRAPHS 


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167]  RATE  OF  REGEXERATIOX—ZELENY  167 


BIBLIOGRAPHY 
Abel  M. 

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191 1.     A  Study  of  the  Relation  of  Tissue  Differentiation  to  Rate  of  Growth 
during  Regeneration.     Biol  Bull.,  21  :  187-206. 
Barfurth,  D. 

1903.     Die    Erscheinungen    der    Regeneration    bei    Wirbeltierembryonen.     O. 
Hertwig's  Handbuch  der  Entwickelungslehre  der  Wirbeltiere. 
Bonnet,  C. 

1745.     Traite    d'insectologie.      Seconde    partie.      Observations    sur    quelques 
especes  de  vers  d'eau  douce,  qui,  coupe  par  morceaux  deviennent  autant 
d'animaux  complets.     Paris. 
Davenport,  C.  B. 

1899.     Experimental  Morphology,  Part  II,  New  York. 
Driesch,  Hans 

1897.  Studien  iiber  das  Regulationsvermogen  der  Organismen,  I.  Von  den 
regulativen  Wachstums-und  Differenzirungs-fahigkeiten  der  Tubularia. 
Arch.  f.  Entw.  Mech.,  5  :389-4i8. 

DuRBiN,  Marion  L. 

1909.    An  Analysis  of  the  Rate  of  Regeneration  Throughout   the  Regener- 
ative Process.    J.  Exp.  Zool.,  7  1397-420. 
Ellis,  M.  M. 

1909.    The   Relation   of   the   Amount   of    Tail   Regenerated   to   the   Amount 
Removed  in  Tadpoles  of  Rana  clamitans.    J.  Exp.  Zool.,  7  :42l-456. 
Em  MEL,  V.  E. 

1906.    The  Relation  of  Regeneration  to  the  Molting  Process  in  the  Lobster. 
Thirty-sixth  Annual  Report  of  the  Commissioners  of  Inland-Fisheries  of 
Rhode  Island.     Special  paper,  no.  27:257-313. 
Kammerer,  Paul 

1905.     L'eber    die    Abhangigkeit    des    Regenerationsvermogens    der   Amphib- 
ienlarven  von  Alter,  Entwicklungsstadium  und  spezifischer  Grosze.    Arch, 
f.  Entw.  Mech.,  19:148-180. 
King,  Helen  D. 

1898.  Regeneration  in  Asterias  vulgaris.    Arch.  f.  Entw.  Mech.,  7:351-363. 
MiNOT,  C.   S. 

1908.     .Age,  Growth  and  Death.    New  York. 


168  ILLINOIS   BIOLOGICAL   MONOGRAPHS  [168 

Morgan,  T.  H. 

1902.  Further  Experiments  on  the  Regeneration  of  the  Tail  of  Fishes.  Arch, 
f.  Entw.  Mech.,  14:539-561. 

1906.  The  Physiology  of  Regeneration.    J.  Exp.  Zool.,  3  :457-50O. 
1909.    The  Dynamic  Factor  in  Regeneration.     Biol.  Bull.,  16 :26s-276. 

MORGULIS,   S. 

1907.  Observations  and  Experiments  on  Regeneration  in  Lumbriculus.  J. 
Exp.  Zool.,  4:549-574. 

igoga.  Regeneration  in  the  Brittle-Star  Ophiocoma  pumila,  with  Special  Ref- 
erence to  the  Influence  of  the  Nervous  System.  Proc.  Amer.  Acad,  of  Arts 
and  Sc,  44:655-659. 

1909b.  Contributions  to  the  Physiology  of  Regeneration.  I.  Experiments  on 
Podarke  obscura.    J.  Exp.  Zool.,  7 :595-642. 

1909c.     Contributions  to  the  Physiology  of  Regeneration.    II.    Experiments  on 
Lumbriculus.    Arch.  f.  Entw.  Mech.,  28:396-439. 
Przibram,  Hans 

1906.  Aufzucht,  Farbwechsel  und  Regeneration  einer  agyptischen  Gottesan- 
beterin  (Sphodromantis  bioculata  Burm).  Arch.  f.  Entw.  Mech.,  22: 
149-192. 

Scott,  G.  G. 

1907.  Further  Notes  on  the  Regeneration  of  the  Fins  of  Fundulus  heterocli- 
tus.     Biol.  Bull.,  12:385-400. 

1909.     Regeneration  in  Fundulus  and  its  Relation  to  the  Size  of  the  Fish. 
Biol.  Bull.,  17:343-353. 
Spallanzani,  Lazaro  Abbe 

1769.     An  Essay  on  Animal  Reproductions.    Translated  by  M.  Maty.    London. 
Stockard,  C.  R. 

1908.  Studies  of  Tissue  Growth,  I.  ./^n  Experimental  Study  of  the  Rate  of 
Regeneration  in  Cassiopea  xamachana.  Carnegie  Institution  Publication 
No.  103  :63-i02. 

1909a.  Studies  of  Tissue  Growth,  II.  Functional  Activity,  Form  Regulation, 
Level  of  the  Cut,  and  Degree  of  Injury  as  Factors  in  Determining  the  Rate 
of  Regeneration.  The  Reaction  of  Regenerating  Tissue  in  the  Old  Body. 
J.  Exp.  Zool.,  6:433--i7i. 
1909b.  Studies  of  Tissue  Growth.  IV.  The  Influence  of  Regenerating  Tissue 
on  the  Animal  Body.  Arch.  f.  Entw.  Mech.,  29:15-32. 
Ubisch,  Leopold  v, 

1915.     Uber  den  Einflusz  von  Gleichgewichtsstorungen  auf  die  Regenerations- 
geschwindigkeit.     Arch.  f.  Entw.  Mech.,  41 :237-2SO. 
Vanlair,  C. 

1894.    Recherches  chronometriques  sur  la  regeneration  des  nerfs.     .Archives 
de  physiologic  normale  et  pathologique.    5^  Serie.,  6:217-231. 
Zeleny,  C. 

1902.  A  Case  of  Compensatory  Regulation  in  the  Regeneration  of  Hydroides 
dianthus.     Arch.  f.  Entw.  Mech.,  13  ;597-6o9. 

1903.  A  Study  of  the  Rate  of  Regeneration  of  the  .Arms  in  the  Brittle-Star, 
Ophioglypha  lacertosa.     Biol.  Bull.,  6:12-17. 


169]  RATE  OF  REGEXERATIOX—ZELENY  169 

iposa.    Compensatory  Regulation.     J.  Exp.  Zool.,  2:1-102. 
iposb.    The  Relation  of  the  Degree  of  Injury  to  the  Rate  of  Regeneration. 
J.  Exp.  Zool.,  2:347-369. 

1907.  The  Effect  of  Degree  of  Injury,  Successive  Injury  and  Functional 
Activity  upon  Regeneration  in  the  Scyphomedusan,  Cassiopea  xamachana. 
J.  Exp.  Zool.,  5:265-273. 

1908.  Some  Internal  Factors  Concerned  with  the  Regeneration  of  the  Chelae 
of  the  Gulf-Weed  Crab  (Portunus  sayi).  Carnegie  Institution  Publica- 
tion No.  103:103-138. 

1909a.  The  Effect  of  Successive  Removal  upon  the  Rate  of  Regeneration.  J. 
Exp.  Zool.,  7:477-512. 

1909b.  The  Relation  between  Degree  of  Injury  and  Rate  of  Regeneration — 
Additional  Observations  and  General  Discussion.    J.  Exp.  Zool.,  7 :5i3-562. 

1909c.  Some  Experiments  on  the  Effect  of  Age  upon  the  Rate  of  Regener- 
ation.   J.  Exp.  Zool.,  7:563-593. 

1912.    The  Quantitative  Study  of  the  Internal  Factors  Controlling  Regenera- 
tion.    Proc.  Seventh  Intern.  Zool.  Congress  1907 :49i-494. 
Zuelzer,  M. 

1907.  Uber  den  Einflusz  der  Regeneration  auf  die  Wachstumsgeschwindig- 
keit  von  .-Xsellus  aquaticus.     Arch.  f.  Entw.  Mech..  25  :36i-397. 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 

Vol.  Ill  October,  1916  No.  2 

Editorial  Committki: 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate   School  nv 

THE  University  of  Illinois 


Coi'YRlGHT,    I915 

By  the  Univkrsity  of  Illinois 
Distributed  December  30,  1916 


THE  HEAD-CAPSULE  AND 
MOUTH-PARTS  OF  DIPTERA 


WITH  TWENTY-FIVE  PLATES 


ALVAH  PETERSON 


Contributions  from  the 
Entomological    Laboratories   of   the    University    of   Illinois   No.    52 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of  Doctor  of  Philosophy  in  Entomology 

in  the  Graduate  School  of  the 

University  of  Illinois 

1915 


TABLE  OF  CONTENTS 


PACE 

Introduction    7 

Methods    8 

Acknowledgments 9 

Materials  9 

Fixed  Parts  of  the  Head 13 

Epicranial  Suture  14 

Fronto-clypeus    17 

Tormae  ..._ 19 

Ptilinum 20 

Labrum   20 

Vertex   21 

Compound  Eyes  and  Ocelli 22 

Occiput  and   Postgenae ; 23 

Tentorium 26 

iSIovable  Parts  of  the  Head 32 

Antennae  : 33 

Mandibles  34 

Maxillae 36 

Labium    4' 

Epipharynx  and   Hypopharynx 49 

Summary 54 

Bibliography 57 

Explanation  of  Plates  6i 


177]  HEAD    OF   DIPTERA  —  PETERSOX 


INTRODUCTION 

The  head  and  mouth-parts  of  Diptera  offer  a  rich  field  for  research. 
A  number  of  excellent  studies  have  been  made  bj'  several  investigators 
and  the}'  deserve  careful  consideration.  A  review  of  practically  all  the 
literature  shows  that  a  majority  of  the  workers  have  examined  only  one 
or  a  few  species.  Meinert  (1881)  and  Hansen  (1883),  however,  studied 
a  number  of  forms,  bvit  they  were  mostly  specialized  species;  wliile  an 
important  study  by  Kellogg  (1899)  deals  only  with  the  families  of  the 
Nematocera.  Becher  (1882)  is  the  only  investigator  who  has  studied  a 
large  series  of  generalized  and  specialized  species.  I  have  made  a  special 
effort  to  secure  as  many  generalized  and  specialized  species  as  possible, 
since  it  is  highly  desirable  and  essential  in  homologizing  structures  to 
have  at  hand  a  wide  range  of  species. 

Extensive  studies  have  not  heretofore  been  made,  so  far  as  I  know, 
on  the  head-capsule;  consequently  the  important  relationship  which  ex- 
ists between  the  mouth-parts  and  the  head-capsule  in  generalized  insects 
has  not  been  traced  in  Diptera.  This  relationship  is  just  as  significant 
in  ascertaining  the  correct  interpretation  of  the  mouth-parts  of  Diptera 
as  it  is  in  other  orders.  Its  importance  is  illustrated  by  a  study  of  the 
head  and  mouth-parts  of  the  Thysanoptera   (Peterson,  1915). 

A  review  of  the  literature,  Dimmock  (1881)  or  Hansen  (1883), 
discloses  the  many  and  varied  interpretations  that  have  been  given  to 
the  mouth-parts  of  Diptera.  To  arrive  at  a  correct  interpretation  of  the 
fixed  and  movable  parts  of  the  head,  the  head-capsule  and  mouth-parts 
of  all  the  species  studied,  irrespective  of  the  established  systematic 
position  of  the  species,  have  been  carefully  compared  with  the'  head  and 
mouth-parts  of  generalized  insects.  On  the  basis  of  this  comparison, 
generalized,  hypothetical  types  have  been  constructed  for  each  fixed 
and  movable  part.  Each  hypothetical  type  is  made  up  by  an  accumu- 
lation of  all  the  generalized  characters  found  among  the  Diptera,  and 
should  show  an  intermediate  stage  between  generalized  insects  and  Dip- 
tera. The  use  of  such  a  hypothetical  type  is  a  great  aid  not  only  in 
showing  how  the  dipterous  type  has  been  developed,  but  also  in  deter- 
mining the  homology  of  the  parts. 

The  scope  of  this  investigation  makes  it  necessary  to  limit  the  dis- 
<;ussions  to  the  general  subject  of  homology;  consequently  many  details 


8  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [17fr 

of  structure  and  other  interesting  modifications,  shown  in  the  figures 
but  without  direct  bearing  on  the  subject  of  homology,  are  necessarily 
disregarded.  The  fixed  and  various  movable  parts  of  the  head  are  dis- 
cussed separately,  as  developed  from  the  hyjiothetical  types,  the  discus- 
sions in  every  case  proceeding  from  the  generalized  to  the  specialized. 

All  the  general  conclusions  pertaining  to  the  head  and  mouth-parts 
presented  in  the  following  pages  are  based  entirely  on  a  study  of  the 
species  listed  under  "materials",  unless  otherwise  stated.  General 
statements  in  respect  to  the  mouth-parts  are  true  only  for  species  having 
them  well  developed. 

The  names  here  adopted  for  the  sclerites  of  the  head  and  mouth- 
parts  have  been  made  to  agree,  so  far  as  possible,  with  the  terms  now 
in  common  use  for  the  same  parts  in  generalized  insects.  The  terms 
most  commonly  used  thruout  the  literature  for  structures  peculiar  to 
this  order  have  been  adopted  unless  clearly  unsuitable ;  and  new  terms 
have  been  applied  only  to  structures  described  here  for  the  first  time 
and  to  parts  to  which  the  current  names  are  inappropriate. 

METHODS 

The  greater  part  of  this  study  was  made  from  dried  specimens  that 
had  been  soaked  from  two  to  twenty-four  hours  in  a  10%  solution  of 
potassium  hydroxide.  The  sclerites  of  weakly  chitinized  forms  show 
more  clearly  when  they  have  been  soaked  for  only  a  short  time.  After 
soaking,  the  heads  were  washed  in  distilled  water  to  remove  the  potas- 
sium h.ydroxide  and  then  preserved  in  70%  alcohol. 

All  dissections  were  made  under  a  binocular  microscope  in  70% 
alcohol  in  deep  watch-glasses  or  in  carbol-aniline  oil.  Studies  and 
figures  were  largely  made  from  dissected  parts  in  alcohol.  Cleared 
preparations  moiinted  in  balsam  were  also  found  useful.  In  making 
such  preparations  the  parts  were  dissected,  stained,  and  cleared  in 
carbol-aniline  oil.  This  oil  evaporates  slowly,  will  mix  readily  with 
safranin  or  orange  G  dissolved  in  95%  alcohol,  and  will  clear  from 
any  grade  of  alcohol  above  50%.  Tlie  staining  of  material  with  safranin 
before  mounting  proved  to  be  very  useful  in  differentiating  the  almost 
colorless  parts  of  some  species.  When  using  aniline  oil  it  is  necessary 
to  remove  as  much  as  possible  of  the  oil  before  mounting,  otherwise  the 
balsam  will  eventually  darken. 

The  material  for  sections  was  fixed  with  hot  (80°  C.)  corrosive 
sublimate  (saturated  corrosive  sublimate  in  35%  alcohol  plus  2%  of 
glacial  acetic  acid)  for  fifteen  minutes  to  two  hours.  This  was  replaced 
by  707(  alcohol  containing  a  few  drops  of  iodine,  and  the  material  was 
allowed  to  remain  in  this  for  twenty-four  or  more  hours.    Paraffin  hav- 


179]  HEAD    OF  DIPTERA  — PETERSON  9 

iug  a  melting:  point  of  62-6-4  C.  was  a  sufficiently  firm  medium  in  which 
to  cut  sections  as  thin  as  eight  microns.  Specimens  stained  in  toto  gave 
the  best  results.  Delafield's  haematoxylin  required  24—48  hours,  and 
borax  carmine  3-7  days. 

ACKNOWLEDGMENTS 

This  investigation  was  carried  on  under  the  supervision  of  Dr. 
A.  D.  MacGillivray,  and  to  him  I  am  greatly  indebted  for  the  sincere 
interest  shown  and  the  many  valuable  suggestions  received.  Many  speci- 
mens, unobtainable  in  this  vicinity,  were  secured  from  the  collections 
of  the  Illinois  State  Laboratory  of  Natural  History,  and  for  these  I  am 
indebted  to  Professor  S.  A.  Forbes.  I  am  indebted  to  the  Graduate 
School  of  the  University  of  Illinois  for  funds  used  in  purchasing  speci- 
mens. I  am  also  indebted  to  Mr.  J.  E.  Malloch,  of  the  Illinois  State 
Laboratory  of  Natural  History,  for  the  identification  of  all  my  material 
and  for  specimens  and  many  suggestions ;  to  Mr.  J.  M.  Aldrich  for 
species  of  Diopsidae,  Phycodromidae,  and  Blephai'oceridae ;  to  Professor 
A.  L.  Melander  for  a  species  of  Cyrtidae ;  to  Mr.  0.  S.  Westcott  for  a 
species  of  Phycodromidae ;  to  Dr.  P.  S.  Welch  for  a  species  of  Simulii- 
dae ;  and  to  Dr.  0.  A.  Johannsen  for  species  of  Dixidae  and  Blepha- 
roceridae.  I  am  also  indebted  to  many  others  wlio  furnished  me  with 
unnamed  material. 

MATERIALS 

Tlie  following  list  of  insects  includes  all  of  the  identified  forms 
studied.  The  families  of  Diptera  to  which  these  species  belong  are 
arranged  according  to  Aldrich 's  "Catalogue  of  North  American  Dip- 
tera". The  generic  and  specific  names  of  all  but  a  few  species  may 
likewise  be  found  in  this  catalog. 

Aldrich  lists  fifty-nine  families;  of  these,  one  or  more  representa- 
tives of  fifty-three  families  have  been  studied.  Tlie  following  are  not 
represented :  Orphnephilidae,  Acanthomeridae,  Nemestrinidae,  Apio- 
ceridae,  Rhopalomeridae,  and  Nycteribiidae.  The  male  and  female  of 
each  species  have  been  observed  except  in  a  few  eases ;  in  these  the  word 
"male"  or  "female"  after  the  species  name  indicates  which  sex  has 
been  seen.  Excepting  one  or  two  forms,  the  male  and  female  have  both 
been  drawn  if  they  were  decidedly  different.  If  the  two  sexes  are 
similar,  the  figures  were  mostly  made  from  the  female.  An  asterisk 
before  the  name  of  a  species  indicates  that  this  form  has  been  embedded, 
sectioned,  and  studied.  The  figures  following  the  various  species  refer 
to  the  drawings  made  of  the  same. 


10  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [180 

DiPTERA 

Suborder  Proboscidea 
Orthorrhapha-Nemocera. 

Tipulidae.— *Tipula  bieornis  (Fig.  18,  95,  178,  277,  383,  384,  388, 
and  503),  Tipula  cunctans,  Tipula  abdominalis,  Limuobia  im- 
matura,  female  (Fig.  93,  386,  and  507),  Helobia  punctipen- 
nis,  female  (Fig.  385),  Trichoeera  bimaeula,  male  (Fig.  16,  78, 
158,  200,  260,  311,  365,  499,  and  500),  Geranomyia  canadensis, 
male  (Fig.  382  and  506),  Ptychoptera  rufocincta  (Fig.  15), 
and  Bittacomorpha  clavipes,  male   (Fig.  85  and  389). 

Dixidae.— Dixa  clavata  (Fig.  19,  79,  163,  199,  262,  375,  387,  501, 
and  502),  and  Dixa  modesta  (Fig.  254). 

Psyehodidae.— Psyehoda  albipennis  (Fig.  8,  82,  166,  202,  263,  318, 
372,  529,  and  530),  and  Psyehoda  sp. 

Chironomidae. — Chironomus  ferugineovittatus  (Fig.  12,  88,  89,  152, 
206,  207,  270,  312,  371,  531,  and  532),  Culieoides  sanguisugus 
(Fig.  253,  265,  and  521),  and  Forcipomyia  cilipes. 

Culicidae.— Psorophora  ciliata  (Fig.  10,  26,  96,  159,  210,  211,  251, 
266,  373,  380,  381,  504,  and  505),  Anopheles  sp.,  and  *Culex  sp. 

Myeetophilidae.— Sciara  varians  (Fig.  17,  81,  150,  205,  267,  314, 
360,  512,  and  513),  Mycetobia  divergens  (Fig.  7,  90,  and  161), 
Myeetophila  punctata  (Fig.  11  and  87),  and  Leia  oblectabilis 
(Fig.  368). 

Cecidomyiidae.— Eabdophaga  strobiloides  (Fig.  6,  86,  170,  201,  268, 
313,  367,  510,  and  511),  and  Cecidomyia  sp. 

Bibionidae.— Bibio  femoratus  (Fig.  13,  14,  91,  92,  153,  154,  208, 
264,  315,  364,  522,  and  523),  and  Bibio  albipennis. 

iSimuliidae. — Simulium  venustum,  female  (Fig.  2,  77,  144,  204,  250, 
258,  316,  366,  489,  497,  and  498),  Simulium  johannseni  (Pig. 
3  and  252),  Simulium  pecuarum,  and  Simulium  jenningsi. 

Blepharoceridae. — Bibioeephala  elegantula  (Fig.  4,  5,  76,  83,  155, 
156,  203,  256,  269,  399,  526,  and  527),  and  Blepharocera  sp. 

Ehyphidae.— Rhyphus  punctatus   (Fig.  9,  80,  157,  209,  261,  321, 
374,  508,  and  509). 
Orthorrhapha-Brachycera. 

Stratiomyiidae.— Stratiomyia  apieula  (Fig.  27,  28,  104,  160,  213, 
273,  331,  395,  396,  545,  and  546),  and  Stratiomyia  meigeni. 

Tabanidae.— Tabanus  giganteus  (Fig.  20,  21,  74,  75,  142,  143,  214, 
255,  259,  283,  317,  390-392,  and  491-496),  Tabanus  sulcifrons, 
Tabanus  atratus,  Tabanus  trimaculata,  and  Chrysops  striatus. 

Leptidae.— Leptis  vertebrata  (Fig.  34,  35, 103, 145,  218,  275,  323,  369, 


181]  HEAD    OF  DIPTERA— PETERSON  11 

370,  520,  and  525),  Chrysopila  proxima,  Chiysopila  thoracica, 

Chrvsopila  quadrata,  and  Chrysopila  velutina. 
Cyrtidae.— Oncodes  costatus  (Fig.  53,  105,  109,  220,  486,  and  487), 

Eulonchus  tristis  (Fig.  284a,  364a,  425a,  425b,  and  543),  and 

Pterodontia  flavipes. 
Bombyliidae.— Exoprosopa  fasciata  (Fig.  29,  98,  162,  216,  285,  361- 

426-429,  549,  and  550),  Systoeehus  vulgaris,  Lepidophora  sp., 

and  Bombylins  major  (Fig.  482). 
Therevidae. — Psilocepliala  liaemorrhoidalis   (Fig.  33,  36,  100,  173, 

281,  324,  402,  403,  533,  and  534). 

Seenopinidae. — Scenopinus  fenestralis   (Fig.  41,  42,  107,  149,  219, 

282,  325,  400,  401,  537,  and  538). 

Mydaidae.— Mydas  clavatus  (Fig.  30,  99,  146,  212,  271,  319,  397, 

398,  535,  and  536). 
Asilidae.— Promachus  vertebra tus  (Fig.  22,  84,  147,  148,  217,  276, 

322,  376-379,  and  517-519),  Asilus  notatus,  and  Derorayia  um- 

brina. 
Dolichopodidae.— Doliehopus  bifractns  (Fig.  43,  112,  168,  226,  284, 

432-434,  524,  and  528),  Doliehopus  sp.   (Fig.  108),  Psilopodi- 

nus  sipho,  and  Sympycnus  lineatus. 
Empididae.— *Empis  clausa   (Fig.  26,  40,  97,  164,  215,  274,  352, 

421-423,  547,  and  548),  Rhamphomyia  glabra   (Fig.  424  and 

425),  and  Euhybus  sp. 
Lonehopteridae.— Lonchoptera  lutea   (Fig.  37,  102,  177,  223,  280, 

320,  406-408,  539,  and  541). 
Phoridae.— Aphiochaeta  agarici   (Fig.  31,  111,  174,  224,  278,  335, 

393,  394,  540,  and  544),  Metopina  sp.,  and  Dohrniphora  con- 

cinna. 
Cyclorrhapha-Atlierieera. 

Platypezidae.— Platypeza  velutina  (Fig.  32,  110,  165,  222,  272,  326, 

415,  416,  542,  and  542a). 
Pipunculidae.— Pipunculus  cingulatus  (Fig.  38,  39,  106,  151,  243, 

279,  327,  435,  436,  561,  and  562). 
Syrphidae.— Eristalis  tenax   (Fig.  23-25,  113,  167,  232,  286,  328, 

441-443,  587,  and  588),  Syritta  pipiens,  and  *Allograpta  ob- 

liqua. 
Conopidae. — Conops  brachyrhynehus  (Fig.  67,  117,  186,  221,  305, 

356,  417-420,  591,  and  592),  Stylogaster  biannulata  (Fig.  359), 

and  Physocephala  tibialis. 
Cyclorrhapha-Calyptratae. 

Oestridae.— Gastrophilus  equi  (Fig.  54,  138,  239,  and  490-492). 
Taehinidae.— Archytas  analis  (Fig.  68,  124,  197,  247,  309,  353,  468, 

469,  604,  and  605),  Siphona  geniculata    (Fig.  355  and  458), 


12  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [182 

Gonia  capitata,  Oeyptera  carolinae,  and  Gymnosoma  fuliginosa. 
Dexiidae.— Thelaira  leucozona  (Fig.  65,  128,  196,  230,  301,  346,  473, 

474,  595,  and  596). 
Sarcophagidae. — Sarcophaga    haemorrhoidalis   (Fig.    66,    130,    191, 

244,  310,  350,  477,  478,  602,  and  603). 
Muscidae.— *Musea  domestica  (Fig.  71,  72,  133,  194,  242,  304,  351, 

465-467,   600,  and  601),   Calliphora  vomitoria    (Fig.  484  and 

485),  *Stomoxys  caleitrans  (Fig.  354,  479,  480,  and  599),  Myios- 

pila  meditabunda    (Fig.   120),  Pollenia  rudis,  Lucilia  caesar, 

and  Calliphora  erytlirocephala. 
Anthomyiidae.— Hydrotaea  dentipes  (Fig.  69,  70,  127,  195,  241,  308, 

349,  475,  476,  597,  and  598),  Lispa  nasoni  (Fig.  116  and  481), 

Dexiopsis  lacteipennis,  Coenosia  aurifrons,  and  Chortophila  sp. 
Cyclorrhapha-Aealyptratae. 

Seatophagidae.— Scatophaga  furcata   (Fig.  62,  135,  193,  246,  307, 

857,  470-472,  593,  and  594). 
Heteroneuridae.— Heteroneura  flaviseta  (Fig.  49,  126,  176,  229,  298, 

340,  459,  460,  589,  and  590). 

Helomyzidae.— Oecothea  fenestralis  (Fig.  48,  137,  192,  227,  290,  332, 

452,  453,  580,  and  581). 
Borboridae.— Borborus  eqiiinus   (Fig.  63,  136,  188,  231,  294,  342, 

437,  438,  and  565-567),  Limosina  ferruginata,  and  Sphaerocera 

piisilla. 
Phycodromidae.— Coelopa  vanduzeii    (Fig.  58,  121,  182,  288,  337, 

448,  449,  559,  and  560). 
Seiomyzidae.— Tetanocera  plumosa  (Fig.  55,  119,  180,  225,  302,  344, 

463,  464,  584,  and  586),  and  Sepedon  fuscipennis. 
Sapromyzidae. — Sapromyza  vulgaris   (Fig.  60,   115,  171,  248,  289, 

329,  409,  410,  553,  and  554),  Sapromyza  bispina,  Miuettia  lupu- 

lina,  and  Lonchaea  polita. 
Ortalididae.— Chrysorayza  demandata  (Fig.  64,  134,  181,  245,  295, 

341,  456,  457,  557,  and  558),  Tritoxa  incurva,  Chaetopsis  aenea, 
Camptoneura  picta,  Pyrgota  sp.,  and  Eumetopia  sp. 

Trypetidae.— Euaresta  aequalis  (Fig.  61,  131,  175,  240,  292,  347, 

413,  414,  572,  and  573),  Trypeta  alba,  and  Straussia  longipen- 

nis. 
Mieropezidae.— Calobata  uuivitta  (Fig.  44,  114,  183,  236,  296,  348, 

446,  447,  551,  and  552). 
Sepsidae.— Sepsis  violacea  (Fig.  46,  118.  184,  234,  287,  334,  439,  440, 

582,  and  583),  and  Prochyliza  xantliostoma. 
Psilidae.— Loxoeera  peetoralis  (Fig.  59,  123,  169,  235,  300,  339,  461, 

462,  570,  and  571). 


183]  HEAD    OF   DIPTERA—PETERSOX  13 

Diopsiclae.— Sphyracephala  bicornis  (Fig.  52.  94,  190,  293,  338,  450, 

451,  and  585). 
Ephydridae.— Ochthera  mantis   (Fig.  56,  101,  187,  237,  297,  336, 

444,  445,  483,  and    574—577),  Paraliinna    appendiculata,    and 

Parydra  bituberculata. 
Oscinidae.— Chloropisca  glabra  (Fig.  51,  132,  189,  306,  345,  430,  431, 

555,  and  556),  Siphonella  abdoniinalis,  and  Hippelates  flavipes. 
Drosopliilidae. — Drosopliila  ampelophila  (Fig.  45,  125,  172,  238,  291, 

343,  454,455,  563,  and  564). 
Geomyzidae.— Chyromya  concolor  (Fig.  50,  122,  179,  233,  299,  333, 

411,  412,  568,  and  569). 
Agromyzidae.— Desmometopa  latipes  (Fig.  47,  129,  185,  228,  303, 

330,  404,  405,  578,  and  579). 

Suborder  Eproboseidea 

Hippoboscidae.— Olfersia  ardeae  (Fig.  57,  139,  198,  249,  358,  488, 
and  606),  and  Melophagus  ovinus. 

Orthoptera 

Periplaneta  orientalis  (Fig.  514). 
IMelanoplus  differentialis  (Fig.  515). 
Grj'llus  pennsylvanicus  (Fig.  516). 

Hypothetical  and  typical  figures  (Fig.  1,  73,  140,  141,  199h,  256h, 
257,  362,  363,  and  493). 

FIXED    PARTS    OF    THE    HEAD 

A  hypothetical  head-capsule  of  Diptera  (Fig.  1)  has  a  dorso-ventral 
extension.  The  epicranial  suture  (e.  s)  is  present  on  the  meson,  and 
extends  from  the  occipital  foramen  (o.  f )  to  a  point  on  the  cephalic 
aspect  ventrad  of  the  antennae.  At  this  point  it  bifurcates  and  the  two 
arms  continue  to  the  invaginations  of  the  anterior  arms  of  the  tentorium 
(i.  a),  which  are  situated  at  the  dorso-lateral  angles  of  the  clypeus  (c). 
The  three  unpaired  sclerites  included  within,  or  ventrad  of,  the  fork  of 
the  epicranial  suture  are  the  front  (fr),  clypeus  (c),  and  labnim  (1). 
The  fronto-elypeal  suture  is  represented  by  a  dotted  line  in  the  figure. 
The  vertex  (v)  includes  all  of  the  dorsal  and  cephalic  aspects  of  the 
epicranium  except  the  front  (fr),  while  the  genae  (ge)  are  the  regions 
of  the  vertex  ventrad  and  mesad  of  the  compound  ej'es.  Two  large 
compound  eyes  (c.e)  cover  the  lateral  portions  of  the  cephalic  aspect. 
Three  ocelli  (oc)  are  situated  on  the  vertex.  The  occiput  (occ)  and 
postgenae  (po)  constitute  the  caudal  aspect  of  the  head-capsule. 


14  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [184- 

The  tentorium  (t)  of  the  hypothetical  head-capsule  has  three  pairs 
of  invaginations,  homologous  with  the  invaginations  in  generalized  in- 
sects. The  invaginations  of  the  posterior  arms  (i.p)  of  the  tentorium 
are  situated  ventrad  of  the  occipital  foramen  at  tlie  distal  ends  of  chitin- 
ized  thickenings.  The  invaginations  of  the  dorsal  arms  of  the  tento- 
rium (i.d)  are  on  the  cephalic  aspect  near  the  antennae  and  adjacent 
to  the  epicranial  suture,  while  the  invaginations  of  the  anterior  arms, 
of  the  tentorium  (i.a)  are  situated  in  the  epicranial  suture  and  adjacent 
to  the  dorso-lateral  angles  of  the  clypeus. 

The  heads  of  all  Diptera  have  a  dorso-ventral  extension,  and  in  this 
respect  resemble  the  heads  of  many  generalized  insects.  Some  of  the 
primary  sutures,  sclerites,  and  invaginations  of  the  head  of  such  an 
insect  are  present  in  a  number  of  tlie  Nematocera  and  in  a  few  of  the 
Brachycera.  The  hypothetical  head-capsule  has  been  constructed  from 
these  forms.  The  heads  of  the  Acalyptratae  and  the  Calyptratae  are 
highly  specialized  by  the  modification,  union,  reduction,  and  membra- 
nous development  of  parts,  consequently  very  few  if  any  primary  char- 
acters remain  which  can  be  homologized  with  these  structures.  The 
membranous  development  of  areas  has  been  the  most  important  process 
of  specialization.  The  stippled  areas  on  the  figures  show  the  extent 
of  the  membrane.  The  various  parts  of  the  head-capsule  are  discussed 
individually  and  in  the  order  in  which  they  were  described  for  the 
hypotlietical  type.  The  heads  of  Diptera  naturally  fall  into  two  groups 
according  to  the  presence  or  absence  of  a  frontal  suture  (fr.s)  and  a 
ptilinum  (pt).  The  forms  without  a  frontal  suture  are  the  more  gen- 
eralized. 

Epicranial  Suture. — The  epicranial  suture  of  all  insects  originates 
in  the  embryo.  The  stem  of  the  suture  on  the  dorso-meson  represents 
the  line  along  which  the  paired  parts  of  the  head  meet,  while  the  arms 
of  the  suture  (a.  e.  s)  represent  the  place  of  contact  between  the  paired 
sclerites  of  the  head  and  the  mesal  unpaired  sclerites.  The  epicranial 
suture  (e.  s)  of  a  hypothetical  dipterous  head  corresponds  to  the  above 
description,  and  is  homologous  with  the  epicranial  suture  found 
in  the  heads  of  generalized  immature  and  adult  insects  of  the  more  com- 
mon orders.  The  following  examples  illustrate  the  homology  between 
the  hypothetical  type  and  other  insects.  The  epicranial  suture  in  the 
larva  of  Corydalis,  and  in  the  generalized  larvae  of  the  Coleoptera,  Lepi- 
doptera,  and  certain  Ilymenoptera,  is  complete,  and  its  two  arms  join 
with  the  margins  of  the  clypeus,  as  in  the  h.ypothetical  type. 

The  epicranial  suture  of  the  adults  of  the  Orthoptera,  Hemiptera, 
and  Hymenoptera  also  resembles  this  suture  in  the  hypothetical  head, 
providing  the  following  interpretation  of  this  suture  is  accepted.     In 


185]  HEAD    OF  DIPTERA— PETERSON  15 

the  adults  of  Gryllus  and  Periplaneta  it  is  complete  and  similar  to  that 
of  Corydalis  except  that  a  small  portion  of  each  arm  is  wanting  about 
the  antennae  and  the  lateral  ocelli.  The  ventral  ends  of  the  arms  are 
commonly  called  the  fronto-genal  sutures,  and  they  join  with  the  clypeus 
as  in  Corj-dalis.  All  insects  that  have  a  sucking  type  of  mouth,  such 
as  the  Hemiptera  and  Hymenoptera,  usually  show  no  signs  of  the  stem 
of  the  epicranial  suture.  The  arms,  however,  are  distinct  and  form  the 
■lateral  and  dorsal  boundaries  of  the  large  mesal  piece  commonly  called 
the  clypeus.  A  large  number  of  the  Diptera  possess  an  epicranial  suture 
which  closely  resembles  that  of  the  Hemiptera  and  the  Hymenoptera. 
On  the  basis  of  the  above  interpretation  of  the  epicranial  suture  it  has. 
been  possible  to  homologize  the  sutures  and  sclerites,  and  the  invagina- 
tions of  the  tentorium  on  the  cephalic  aspect.  No  other  interpretation 
gave  satisfactory  results. 

The  epicranial  suture  (e.  s)  in  Mycetophila  (Fig.  11)  is  complete 
and  closely  resembles  the  hypothetical  type.  In  Leia  it  closely  resem- 
bles that  of  Mycetophila  except  for  the  stem  of  the  suture,  which  is 
wanting  dorsad  of  the  median  ocellus.  The  stem  of  the  epicranial  suture 
in  Psorophora  (Fig.  10  and  26)  and  Chironomus  (Fig.  12)  is  repre- 
sented by  a  distinct  suture  in  a  deep  fold  on  the  meson.  Other  forms, 
such  as  Rhabdophaga  (Fig.  6),  Mycetobia  (Fig.  7),  and  Tabanus  (Pig. 
20),  show  depressions  or  thickenings  along  the  meson.  These  marks 
may  have  no  significance.  Outside  of  the  above-mentioned  forms,  the 
stem  of  the  epicranial  suture  is  wanting. 

The  arms  of  the  epicranial  suture  (a.  e.  s)  are  present  in  many 
Diptera.  This  is  the  case  in  all  but  a  few  of  the  Nematocera,  in  a  ma- 
jority of  the  Brachycera,  and  in  many  of  the  families  of  the  Cyclorrha- 
pha.  These  resemble,  therefore,  the  adults  of  the  Hemiptera  and  Hy- 
menoptera. The  arms  are  present  as  definite  sutures  between  two 
chitinized  areas  in  Tabanus  (Fig.  20  and  21)  and  Leptis  (Fig.  33), 
and  in  the  female  of  Simuliura  (Fig.  2).  The  epicranial  suture  is  ap- 
parently wanting  in  the  male  of  Simulium  (Fig.  3)  unless  the  lateral 
margins  of  the  convex  area  represent  it.  In  many  genera  the  epicranial 
suture  is  represented  by  the  edge  of  a  chitinized  sclerite.  This  is  the 
case  in  Chironomus  (Fig.  12),  Trichocera  (Fig.  16),  Psorophora  (Pig. 
10),  Mycetobia  (Fig.  7),  and  Dixa  (Pig.  19).  The  vertex  in  the  genera 
just  named  is  membranous  between  the  antennal  fossae  and  the  epicra- 
nial suture.  Sciara  (Pig.  17),  Rhabdophaga  (Pig.  6),  Bibiocephala  (Fig. 
4  and  5),  and  possibly  Rhyphus  (Fig.  9)  and  Bibio  (Fig.  14),  have 
the  arms  of  the  epicranial  suture  represented  by  the  chitinized  margin 
of  the  vertex,  which  is  adjacent  to  the  membranous  portion  of  the 
fronto-clypeus.     The  location  of  the  invaginations  of  the  arms  of  the 


16  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [186 

tentorium  usually  helps  to  determine  the  location  of  the  epicranial  su- 
ture. In  Ptychoptera  (Fig.  15)  the  invaginations  of  the  anterior  arms 
of  the  tentorium  are  located  in  the  distinct  V-shaped  depression  on  the 
chitinized  area  ventrad  of  the  antennae.  Undoubtedly  this  depression 
marks  the  position  of  the  epicranial  suture.  Tipula  (Fig.  18)  has  a 
very  specialized  head  and  shows  no  epicranial  suture  or  tentorium. 

Only  the  arms  of  the  epicranial  sutures  are  present  in  the  Brachyc- 
-era.  On  the  whole  these  sutures  are  not  as  well  developed  in  the 
Brachycera  as  in  the  Nematocera.  When  present  (a.  e.  s)  they  are  long 
and  slit-like  in  all  the  genera  except  Tabanus.  This  condition  is  due 
to  the  fusion  of  the  invaginations  of  the  dorsal  arms  and  the  anterior 
arms  of  the  tentorium  along  each  suture.  The  arms  of  this  suture  in 
Tabanus  (Fig.  20  and  21)  unite  the  invaginations  on  each  lateral  half 
of  the  head,  but  they  are  not  decidedly  slit-like. 

The  arms  of  the  epicranial  suture  (a.  e.  s)  in  Tabanus  (Fig.  20) 
have  the  usual  inverted-u  shape  and  their  ventral  ends  terminate  at  the 
ventral  margin  of  the  head.  The  arms  are  indistinct  ventrad  of  the 
invaginations  of  the  anterior  arms  of  the  tentorium.  The  invaginations 
(i.  a)  in  Promachus  (Pig.  22)  are  slit-like  and  situated  near  the  ventro- 
lateral angles  of  the  compound  eyes.  The  epicranial  suture  is  wanting 
dorsad  and  ventrad  of  the  invaginations  of  the  anterior  arms,  and  in 
this  respect  Promachus  differs  from  Leptis  and  Tabanus.  From  Leptis 
(Fig.  35)  it  is  possible  to  homologize  the  arms  of  the  epicranial  suture 
of  all  the  Brachycera  and  those  of  the  Cyclorrhapha.  The  arms  of  the 
suture  in  Leptis  are  long  and  slit-like  and  coincide  with  the  invagina- 
tions of  the  tentorium  on  the  cejihalic  aspect  of  the  head.  They  extend 
dorsad  from  the  ventral  margin  of  the  head  to  a  point  ventrad  of  the 
antennae,  where  they  unite  and  enclose  a  convex  mesal  area  called  the 
fronto-clypeus  (fr.  c).  This  siiture  (a.  e.  s)  in  Platypeza  (Fig.  32) 
closely  resembles  that  of  Leptis.  The  dorsal  ends  of  the  arms  of  the 
epicranial  suture  are  wanting  in  Psilocephala  (Fig.  36),  Mydas  (Fig. 
30),  Exoprosopa  (Fig.  29),  Eristalis  (Fig.  23  and  25),  and  Scenopiuus 
(Pig.  41  and  42),  and  in  other  forms.  Scenopinus  shows  a  striking 
variation  in  that  the  vertex  is  membranous  between  the  antennae  and 
the  fronto-clypeus,  and  no  epicranial  suture  can  be  traced  thru  the 
membrane.  Stratiomyia  (Fig.  27)  shows  a  unique  development  of  the 
slits  in  that  they  extend  mesad  rather  than  dorsad.  This  condition  is 
undoubtedly  a  secondary  development.  The  epicranial  suture  of  Lon- 
choptera,  Aphiochaeta,  Pipunculus,  and  Empis  is  discussed  under  fronto- 
clypeus. 

No  epicranial  suture  or  slit-like  invaginations  are  present  in  any 
dipteron  that  has  a  frontal  suture   (fr.  s)   or  a  ptilinum   (pt).     Since 


187]  HEAD    OF  DIPTERA— PETERSON  17 

the  tentorium  on  the  cephalic  aspect  and  the  arms  of  the  epicranial 
suture  are  usually  closely  associated  in  insects,  there  is  every  reason  to 
believe  that  the  tentorial  thickenings  (t.  th)  mark  the  course  of  the 
suture  (a.  e.  s).  Furthermore,  the  location  of  the  thickenings  of  the 
tentorium  is  very  similar  to  the  location  of  the  slit-like  invaginations 
of  Leptis  (Fig.  35).  These  thickenings  (t.  th)  have  been  considered  as 
marking  the  course  of  the  arms  of  the  epicranial  suture.  The  extent 
of  the  tentorial  thickenings  varies  considerably,  as  shown  in  the  figures. 
In  Tetauocera  (Fig.  55),  Chloropisca  (Fig.  51),  Heteroneura  (Fig.  49), 
and  others,  the  tentorial  thickenings  extend  to  the  antennal  fossae  (a.  f). 
No  sutures  are  present  between  the  dorsal  ends  of  these  thickenings. 

Fronto-clypeus. — The  front  (fr)  and  clj^aeus  (c)  of  all  insects  are 
unpaired  selerites  located  between  the  arms  of  the  epicranial  suture 
(a.  e.  s).  The  labnim  (1)  is  also  an  unpaired  sclerite  attached  typically 
to  the  ventral  margin  of  the  clypeus.  These  three  selerites  and  their 
parts  are  not  always  distinguishable.  This  is  particularly  true  of  the 
front  and  clypeus  in  Diptera.  The  dotted,  transverse  line  uniting  the 
invaginations  of  the  anterior  arms  of  the  tentorium  (i.  a)  in  the  hypo- 
thetical head  indicates  the  position  of  the  fronto-elypeal  suture.  In  a 
few  of  the  Orthorrhapha,  suture-like  marks,  depressions,  or  thickenings 
extend  across  the  ehitinized  portion  of  the  fronto-clj^eus.  These  marks 
in  Chironomus  (Fig.  12),  Mj'cetophila  (Fig.  11),  and  Rhabdophaga 
(Fig.  6)  resemble  the  fronto-elypeal  siiture  as  indicated  in  the  hypo- 
thetical type.  It  is  possible  that  they  are  remnants  of  this  suture. 
Excepting  in  the  forms  named,  one  can  not  be  sure  of  the  presence  of 
a  f ronto-ch^eal  suture ;  consequentlj'  the  entire  area  between  tlie  labrum 
and  the  arms  of  the  epicranial  suture  has  been  designated  as  the  fronto- 
clypeus  (fr.  c).  The  absence  of  the  fronto-elypeal  suture  in  Diptera 
is  not  unusual,  since  it  is  wanting  in  many  generalized  insects.  For 
those  who  may  wish  to  di\'ide  the  fronto-clj'peus  into  two  areas,  the 
dorsal  half  would  be  the  front  and  the  ventral  half  the  clypeus.  A 
large  portion  of  the  fronto-clypeus  is  membranous  in  Rhabdophaga  (Fig. 
6),  Rhyphus  (Fig.  9),  and  Seiara  (Fig.  17),  and  the  ehitinized  part 
is  greatly  reduced.  The  variations  found  in  the  Nematocera  are  rep- 
resented in  the  figures. 

The  Brachycera  show  two  lines  of  development  in  the  modification 
of  the  area  enclosed  by  the  arms  of  the  epicranial  suture.  Both  of  these 
started  from  a  form  which  possessed  an  epicranial  suture  similar  to  that 
of  Leptis  (Fig.  35).  The  line  of  development  seen  in  Psilocephala, 
Platypeza,  Scenopinus,  Lonchoptera,  and  Aphiochaeta  is  considered  first. 
The  ehitinized  fronto-clypeus  of  Leptis  resembles  the  fronto-clypeus  of 
a  number  of  the  Nematocera,  as  Seiara   (Fig.  17).     From  tliis  simple 


18  ILLIKOIS  BIOLOGICAL  MONOGRAPHS  [188 

condition  it  is  possible  to  develop  the  type  of  fronto-clypeus  found  in 
Psilocephala  (Fig.  33  and  36).  This  came  about  by  a  membranous 
development  on  the  meson  and  on  the  lateral  margins  of  the  fronto- 
clypeus  and  the  loss  of  the  arms  of  the  epicranial  suture  directly  ven- 
trad  of  the  antennae.  The  membranous  development  of  the  fronto- 
clypeus  of  Platypeza  (Fig.  32)  resembles  that  of  Psilocephala.  Sceno- 
pinus  (Fig.  41  and  42)  belongs  to  this  same  line,  but  in  this  genus  the 
antennae  are  adjacent  to  the  fronto-clypeus  and  no  portion  of  the 
ehitinized  vertex  exists  between  them.  The  form  of  the  chitiuized 
portion  of  the  fronto-clypeus  resembles  closely  that  of  Platypeza  (Fig. 
32).  Aphiochaeta  (Fig.  31)  and  Lonchoptera  (Fig.  37)  apparently 
belong  to  this  same  series.  If  such  is  the  case,  the  arms  of  the  epici'auial 
suture  do  not  project  dorsad  but  are  represented  by  the  nearly  straight 
ventral  margin  of  the  cephalic  aspect.  This  condition  must  have  come 
about  by  the  straightening  out  of  the  usual  u-shaped  depression,  and 
the  ehitinized  part  of  the  fronto-clypeus  is  located  ventrad  of  the  mar- 
gin of  the  head.  The  tentorial  thickenings  along  the  ventral  margin 
of  the  head  in  Lonchoptera  afford  evidence  favorable  to  the  above  inter- 
pi'etation.  A  similar  type  of  development  occurs  in  Bibio  (Fig.  14), 
in  ■whicli  the  invaginations  for  the  anterior  arms  of  the  tentorium  are 
located  on  the  ventral  margin  of  the  head-capsule  latero-ventrad  of 
the  antennal  fossae.  All  the  other  Brachyeera  and  Cyclorrhapha  figured, 
show  the  presence  of  sclerites  designated  as  the  tormae  and  located 
ventrad  of  the  fronto-clypeus,  and  this  fact  places  them  in  tlie  line  of 
specialization  which  leads  toward  a  muscid  type. 

The  fronto-clypeus  (fr.  c)  is  present  in  all  Diptera  and  constitutes 
a  prominent  portion  of  the  head-capsule.  In  Tabanus  (Fig.  20  and 
21)  the  fronto-clypeus  is  the  entire  area  ventrad  of  the  epicranial  suture 
and  outside  of  the  tormae  and  the  labrum.  The  sutures  separating  the 
fronto-clypeus  from  the  genae  (ge)  are  very  indistinct.  No  arms  of 
the  epicranial  suture  are  present  in  Promachus  (Fig.  22),  Empis  (Fig. 
40),  and  Pipunculus  (Fig.  38)  ;  consequently  the  dorsal  extent  of  the 
fronto-clypeus  can  not  be  determined,  and  the  area  ventrad  of  the 
antennae  is  considered  as  the  fronto-clypeus.  The  fronto-clypeus  of 
My  das  (Fig.  30)  resembles  that  of  Leptis,  and  from  a  type  similar  to 
Mydas  it  is  possible  to  develop  the  fronto-clypeus  of  Exoprosopa  (Fig. 
29),  Eristalis  (Fig.  25),  and  probably  Stratiomyia  (Fig.  27).  The 
fronto-clypeus  of  Mydas  closely  resembles  that  of  the  Acalyptratae  and 
tlie  Calyptratae,  as  will  be  seen  by  comparing  Mydas  with  Tetanocera 
(Fig.  55),  Chloropisca  (Fig.  51),  Chyromya  (Fig.  50),  and  Musca  (Fig. 
72).  It  is  not  a  completely  ehitinized  area  in  all  of  the  genera  studied, 
and  the  significance  of  this  mesal  membranous  area  in  Sepsis,  Oecothea, 
and  Calobata  has  been  suggested  in  the  discussion  on  the  ptilinum. 


189]  HEAD    OF  DIPTERA— PETERSON  19 

Tonnac. — The  tormae  (to)  in  generalized  insects  are  cliitioized 
pieces  which  belong  to  the  lateral  portions  of  the  epipharynx  in  the 
region  of  the  clypeo-labral  suture  and  connect  with  the  cljT)eus  or  la- 
brum  at  the  lateral  ends  of  the  suture.  These  are  well  illustrated  in  such 
Orthoptera  as  Periplaneta  (Pig.  514),  Melanoplus  (Fig.  515),  and 
GryUus  (Fig.  516). 

The  tormae  of  generalized  Diptera  also  connect  with  the  inner  sur- 
face of  the  ventral  portion  of  the  frouto-clypeus.  They  are  not  well- 
developed  structures  or  readily  distinguishable  from  the  fronto-cl.vpeus 
in  a  number  of  species  of  the  Nematocera.  This  seems  to  be  due  to  the 
decidedly  convex  nature  of  the  fronto-clypeus  and  the  close  proximity 
of  its  lateral  portions  to  the  lateral  margins  of  the  epipharynx.  The 
tormae  of  Leptis  (Fig.  520),  Psilocephala  (Fig.  36  and  533),  Scenopi- 
nus  (Fig.  41  and  538),  Aphiochaeta  (Fig.  31  and  544)  Louchoptera 
(Fig.  37  and  539),  and  Platypeza  (Fig.  32  and  543)  connect  with  the 
fronto-clypeus  and  thus  resemble  the  Nematocera  and  the  hypothetical 
type.  In  Tabanus,  the  tormae  (Fig.  494)  resemble  the  above  genera  in 
their  connection  with  the  fronto-clypeus,  but  they  have  been  enlarged 
ventrad  until  they  are  exposed  between  the  clypeus  and  the  labrum 
(Fig.  20  and  494).  The  exposed  portions  of  the  tormae  resemble  two 
small,  triangular  sclerites  with  their  pointed  ends  meeting  on  the  meson. 
This  condition  is  not  unusual  since  they  resemble  closely  the  exposed 
portions  of  the  tormae  located  at  the  lateral  ends  of  the  clypeo-labral 
suture  in  Gryllus  (Fig.  516).  Siraulium  (Fig.  2  and  489)  also  shows 
exposed  portions  of  the  tormae  at  the  ventro-lateral  angles  of  the  fronto- 
clypeus  (fr.  c). 

The  inverted  chitinized  V-shaped  piece  ventrad  of  the  fronto- 
clypeus  in  Mydas  (Fig.  30)  has  undoubtedly  been  derived  from  the  fusion 
of  the  tormae  of  some  form  resembling  Tabanus  (Fig.  20).  The  tor- 
mae are  adjacent  to  the  fronto-clypeus  in  Mydas,  but  they  are  not  con- 
nected with  the  same  as  in  Tabanus.  From  the  type  of  tormae  found 
in  Mydas  it  is  possible  to  develop  the  tormae  of  all  other  genera.  The 
tormae  vary  in  shape  and  position  as  seen  in  the  cephalic  views  of  the 
head.  In  Exoprosopa  (Fig.  29),  Eristalis  (Fig.  25),  and  Stratiomyia 
(Fig.  27)  they  show  a  striking  development  in  that  they  are  located 
within  deep  emarginations  of  the  ventral  nuirgin  of  the  fronto-clypeus. 
The  tormae  of  Empis  (Fig.  40)  closely  resemble  those  of  IMydas  and 
belong  to  the  same  line  of  development.  In  Pipunculus  (Fig.  38)  the 
tormae  resemble  the  fronto-clypeus  of  Sciara  (Fig.  17),  but  as  a  matter 
of  fact  the  fronto-clypeus  is  the  area  ventrad  of  the  antennae,  as  shown 
by  the  location  (Fig.  151)  of  the  dorsal  arms  of  the  tentorium  (d.  a). 
The  tormae  of  the  Acal.vptratae  are  usually  crescent-shape,  while  in  the 
Calyptratae  they  resemble  the  type  found  in  Mydas. 


20  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [190 

Ptillnum. — A  deep,  inverted  U-shaped  groove  is  present  in  the 
heads  of  all  the  Calyptratae  and  the  Acalyptratae  dorsad  of  the  anten- 
nae. This  groove  is  called  the  frontal  suture  (fr.  s)  and  marks  the  line 
of  invagination  of  the  large  membranous  pouch,  the  ptilinum  (pt).  In 
Sphyracephala  (Fig.  52)  the  frontal  suture  is  V-shaped,  owing  to  the 
peculiar  development  of  the  head.  The  extent  of  the  invagination  of 
the  ptilinum  (pt)  is  indicated  by  a  dot-and-dash  line  in  the  drawings 
of  the  cephalic  and  lateral  views  of  the  head-capsule. 

The  origin  of  the  ptilinum  has  been  a  mystery  to  morphologists. 
After  a  careful  examination  of  the  heads  of  the  Brachyeera  and  the 
Cyelorrhapha,  no  definite  data  were  found  which  would  throw  any  light 
on  its  origin.  A  few  forms,  however,  suggested  a  possible  way  in  which 
it  might  have  been  developed.  The  frontal  suture  and  the  ptilinum 
are  comparatively  small  in  Tetanocera  (Fig.  55),  Sapromyza  (Fig.  60), 
Conops  (Fig.  67),  Oehthera  (Fig.  56),  and  Chloropisea  (Fig.  51). 
These  genera  gave  no  clue  to  the  early  stages  of  its  development  unless 
the  thinly  chitinized  condition  of  the  fronto-cl.ypeus  of  Chloropisea  has 
some  significance.  It  seems  evident  that  the  frontal  suture  was  once  a 
membranous  area  which  became  invaginated  to  form  a  membranous 
pouch  or  ptilinum.  If  this  is  the  case,  the  mesal  membranous  area  of 
the  fronto-clypeus  of  Sepsis  (Fig.  46),  Oecothea  (Fig.  48),  Calobata 
(Fig.  44),  and  Desmometopa  (Fig.  47)  would  be  very  significant.  The 
ptilinum  might  possibly  have  originated  from  some  form  similar  to 
Scenopinus  (Fig.  41),  in  which  the  ventral  margin  of  the  chitinized 
vertex  is  located  dorsad  and  laterad  of  the  antennae.  It  seems  quite 
possible  that  the  membrane  along  this  margin  became  invaginated  in 
the  early  stages  of  the  development  of  the  ptilinum.  The  above  con- 
jectures may  or  may  not  be  correct.  A  real  solution  of  the  problem  will 
undoubtedly  require  a  careful  study  of  the  pupal  development. 

Lahrum. — The  labrum  (1)  of  a  hypothetical  dipterous  head  (Fig. 
1,  140,  and  493)  is  a  distinct,  chitinized,  tongue-like  structure  connected 
with  the  ventral  margin  of  the  clypeus.  The  shape  and  size  of  the 
labrum  are  identical  with  the  shape  and  size  of  the  epipharynx,  which 
is  located  on  its  caudal  aspect.  The  labrum  {1)  and  epipharynx  (ep) 
are  joined  together  by  a  membrane  along  their  lateral  margins.  These 
two  structures  thus  act  as  one  organ  and  they  have  rightly  been  called 
the  labrum-epipharynx  (1.  ep).  The  above  relation  of  the  labrum  to 
the  epipharynx  and  the  fronto-clj^jeus  resembles  that  in  the  Orthoptera. 

In  a  general  way  the  labrum  of  all  the  genera  studied  resembles  the 
hypothetical  type  described  above.  It  varies,  however,  in  shape  and 
in  degree  of  ehitinization.  In  Promachus  (Fig.  22),  in  Psorophora  (Fig. 
10  and  26),  and  in  the  female  of  Tabanus  (Fig.  20)  it  is  completely 


191]  HEAD    OF  DIPTERA— PETERSON  21 

eliitinized  aud  separated  from  the  fronto-elypeus  by  a  suture.  In  all 
other  genera  there  is  a  distinct  membranous  area  present  between  the 
fronto-elypeus  and  the  labrum.  This  area  is  very  extensive  in  the 
Cyclorrhapha  and  includes  the  ectal  exposure  of  the  tormae.  The  la- 
brum of  a  few  scattered  genera,  such  as  Rhabdophaga  (Fig.  6),  Myeeto- 
bia  (Fig.  7),  Chironomus  (Fig.  12),  Seenopinus  (Fig.  41),  and  others, 
is  completely  membranous,  while  in  still  others  it  is  nearly  so,  as  in 
Mydas  (Fig.  30).  The  figures  of  the  cephalic  aspect  of  the  head  and 
the  lateral  views  of  the  epipharynx  aud  the  hypopharynx  show  the 
shape  and  extent  of  the  chitinization  of  the  labrum. 

The  labrum  of  Dixa  (Fig.  501),  Trichocera  (Fig.  499),  Sciara 
(Fig.  513),  Bibio  (Fig.  523),  Simulium  (Fig.  497),  Culicoides  (Fig. 
521),  Tabanus  (Fig.  20),  and  Dolichopus  (Fig.  528)  is  di.stinctly  sepa- 
rated from  the  epipharynx  (ep)  by  a  membrane.  This  condition  is 
best  seen  in  a  lateral  view.  A  majority  of  the  forms  studied  have  little 
or  no  membrane  between  the  labrum  and  epipharynx.  This  is  particu- 
larly true  of  the  Cyclorrhapha.  The  surface  of  the  labrum  of  all  Dip- 
tera  is  more  or  less  convex.  In  a  large  number  of  the  genera  the  con- 
vexity is  very  decided  and  of  such  a  nature  as  to  surround  the  cephalic 
and  lateral  aspects  of  the  epipharynx.  The  epipharynx  in  these  forms 
can  only  be  seen  in  a  caudal  view.  In  the  Calyptratae,  the  labrum  and 
epipharynx  are  firmly  united  in  one  piece. 

The  labrum  of  Simulium  (Fig.  2  and  489)  is  unique  in  that  the 
chitinized  part  consists  of  a  narrow  mesal  piece  which  bifurcates  at  its 
distal  end.  These  bifurcations  give  rise  to  special  small  liook-like  struc- 
tures (h)  which  have  been  incorrectly  interpreted  as  mandibles  (Smith, 
1890).  The  labrum  and  epipharynx  of  Psorophora  (Fig.  504)  fit  to- 
gether very  closely.  By  careful  dissection  they  may  be  separated,  as 
seen  in  the  drawing.  So  far  as  observed,  no  membrane  is  present  be- 
tween them.  The  proximal  end  of  the  labrum  is  crook-like  in  form, 
and  muscles  connect  with  this  portion. 

Vertex. — The  vertex  (v)  of  a  hypothetical  head  (Fig.  1)  consists 
of  the  paired  continuous  areas  on  the  cephalic  aspect  of  the  epicranium. 
It  is  interpreted  as  including  all  the  cephalic  and  dorsal  aspects  of  the 
epicranium  except  the  front.  In  a  number  of  the  Diptera,  as  heretofore 
described,  the  stem  of  the  epicranial  suture  (s.  e.  s)  is  present  and  marks 
the  line  of  fusion  of  the  two  halves  of  the  vertex,  upon  which  the  ocelli 
and  the  antennae  are  located.  The  shape  and  size  of  the  chitinized 
portion  of  the  vertex  is  largely  determined  by  the  size  of  the  compound 
eyes,  the  location  and  extent  of  the  membranous  area  about  the  base 
of  the  antennae,  and  the  location  of  the  arms  of  tlie  epicranial  suture. 
The  variations  in  the  size  and  shape  of  the  vertex  are  .shown  in  the  figures 
of  the  cephalic  aspect  of  the  head. 


22  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [192 

The  region  of  the  vertex  ventrad  and  mesad  of  each  compound 
eye  is  a  gena.  The  size  of  the  genae  (ge)  is  dependent  upon  the  location 
of  the  compound  eyes  and  the  ventral  extension  of  the  head-capsule. 
The  figures  show  considerable  variation  in  these  respects. 

Compound  Eyes  and  Ocelli. — The  compound  eyes  (c.  e)  of  a  hypo- 
thetical head  are  large  oval  structures  located  on  the  cephalo-lateral 
aspects  of  the  head-capsule.  They  cover  from  one-half  to  two-thirds 
of  the  entire  cephalic  aspect  and  their  caudal  margins  are  adjacent  to 
the  lateral  margins  of  the  head.  The  compound  eyes  of  a  majority  of 
the  Diptera  resemble  in  general  the  hypothetical  type.  The  shape  and 
size  vary  considerably  with  the  different  species.  Variations  are  most 
prevalent  in  the  families  of  the  Orthorrhapha.  This  variability  agrees 
with  the  decided  variability  of  other  parts.  In  such  genera  as  Tipula 
(Pig.  95),  Psorophora  (Fig.  96),  and  Limnobia  (Fig.  93)  the  compound 
eyes  are  exceptional  in  that  they  extend  onto  the  caudal  aspect  of  the 
liead.  The  variations  in  shape  are  well  illustrated  by  the  numerous 
figures. 

The  compound  eyes  show  secondary  characters  in  a  greater  number 
of  species  than  any  other  fixed  or  movable  part.  This  sexual  variation 
is  most  prevalent  among  the  Nematoeera  and  the  Brachycera,  and  was 
not  observed  in  the  Acalyptratae.  Among  the  Calyptratae,  slight 
differences  occur  in  Musca  (Fig.  71  and  72)  and  Hydrotaea  (Fig.  69 
and  70).  When  sexual  variation  occurs,  the  eyes  of  the  male  are  larger 
than  those  of  the  female,  and  they  are  usually  adjacent  along  a  portion 
of  their  mesal  margins.  Such  species  are  said  to  be  holoptic ;  while  all 
the  females,  and  some  of  the  males,  having  the  eyes  distinctly  separated, 
are  dichoptic.  The  extent  of  the  holoptic  condition  depends  upon  the 
size  of  the  eyes  and  the  location  of  the  antennal  fossae,  as  in  Simulium 
(Fig.  2  and  3)  and  Bibio  (Fig.  13  and  14).  In  the  male  of  Bibio  the 
compound  eyes  are  adjacent  along  their  mesal  margin  and  the  antennal 
fossae  (a.  f )  are  located  ventrad  of  the  eyes.  The  extent  and  nature 
of  the  sexual  variation  is  shown  in  the  figures.  Except  in  the  case  of 
Empis  the  heads  of  the  male  and  female  have  both  been  drawn  when 
decided  differences  are  present. 

The  facets  or  ommatidia  of  the  compound  eyes  vary  in  number, 
form,  and  size  thruout  the  order.  In  the  Nematoeera  they  are  usually 
large  and  not  as  closely  compacted  as  in  the  Cyclorrhapha.  An  inter- 
esting variation  occurs  in  the  male  of  Simulium,  the  facets  (fa)  of  the 
ventral  half  of  the  eye  being  smaller  than  those  of  the  dorsal  half.  This 
difference  is  also  foi;nd  in  the  female  of  Bibiocephala  (Fig.  5).  In  the 
male  of  Bibio  (Fig.  154)  the  facets  (fa)  in  the  ventro-caudal  portions 
of  the  eyes  are  smaller  than  the  others.  The  compound  eyes  of  Bibio- 
cephala and  Blepharocera  are  divided  into  a  dorsal  and  a  ventral  por- 


193]  HEAD    OF  DIPTERA  — PETERSON  23 

tion  by  a  transverse  constriction  (eh),  where  the  ommatidia  are  wanting. 
This  constriction  is  also  present  in  Bibio,  but  in  this  form  it  is  confined 
to  the  caudo-ventral  portion  of  the  eye. 

The  drawings  of  the  lateral  aspects  of  some  heads  show  a  line  of 
dashes  or  a  solid  line  around  the  margins  of  the  compound  eyes.  This 
line  indicates  the  extent  of  the  infolding  of  the  head-capsule  adjacent 
to  the  compound  eye.  This  infolding,  or  ocular  sclerite  (o.  s),  is  figured 
only  for  those  species  in  which  it  is  closely  related  to  the  external  mark- 
ings found  on  the  caudal  aspect  dorsad  of  the  occipital  foramen.  The 
influence  of  this  invaginated  edge  will  be  more  fully  discussed  later. 

The  three  ocelli  (oc)  of  the  hypothetical  head-capsule  (Fig.  1)  are 
arranged  in  the  form  of  a  triangle  and  located  on  the  cephalo-dorsal 
aspect  of  the  vertex.  The  median  ocellus  is  in  the  epicranial  suture, 
somewhat  ventrad  of  the  lateral  ocelli.  In  Leia  it  is  in  this  suture 
somewhat  dorsad  of  the  bifurcation,  and  the  other  two  ocelli  are  some- 
what laterad  of  it.  This  location  of  the  ocelli  in  the  Diptera  agrees 
with  Comstock's  idea  concerning  the  caudal  migration  of  the  ocelli  in 
specialized  insects.  In  generalized  insects  all  three  ocelli  may  be  on  the 
front  or  two  on  the  vertex  while  the  median  ocellus  is  on  the  front. 
The  ocelli  in  the  Hymenoptera  and  Hemiptera  are  similar  in  location  to 
those  of  the  Diptera. 

Leia  is  the  only  form  studied  which  has  ocelli  and  a  well-marked 
stem  of  the  epicranial  suture.  The  chitinized,  secondary,  Y-sliaped 
thickenings  on  the  ocellar  triangle  of  Rhyphus  (Fig.  9)  and  Mycetobia 
(Fig.  7)  should  not  be  confused  with  the  epicranial  suture.  Three  ocelli 
are  present  in  all  other  genera  of  Diptera  examined  except  Oncodes  (Fig. 
53)  and  Mycetophila,  in  which  there  are  only  two.  The  median  ocellus 
is  wanting  in  Mycetophila,  while  the  lateral  ocelli  are  small  inconspicuous 
bodies,  adjacent  to  the  dorso-mesal  margin  of  the  compound  eyes  (not 
shown  in  the  figure).  The  figures  show  such  variations  as  occur  in  the 
various  ocellar  groups. 

Occiput  and  Postgenae. — No  sutures  occur  on  the  caudal  aspect  of 
the  hypothetical  head-capsule  (Fig.  73)  except  the  epicranial  suture 
(e.  s).  This  absence  of  sutures  makes  it  impossible  to  locate  definitely 
the  boundaries  of  the  occiput  and  the  postgenae.  The  following  in- 
terpretation is  based  iipon  a  study  of  the  occiput  and  postgenae  of 
generalized  insects,  .such  as  the  Orthoptora.  The  occiput  comprises  aU 
the  area  dorsad  of  an  imaginary  transverse  line  drawn  thru  the  middle 
of  the  centrally  located  occipital  foramen.  The  areas  ventrad  of  this 
line  and  laterad  of  the  mesal  membranous  areas  are  the  postgenae.  The 
occiput  (occ)  undergoes  a  secondary  development  about  the  margin  of 


24  ILLIXOIS  BIOLOGICAL  MOSOGRAPHS  [194 

the  occipital  foramen.  The  structures  pertaining  to  this  modification 
have  been  designated  as  the  parocciput  (pocc).  Each  postgena  (po) 
is  also  secondarily  differentiated  along  its  mesal  margin  by  a  chitinized 
thickening  which  extends  between  the  occipital  foramen  and  the  invagi- 
nations of  the  posterior  arms  of  the  tentorium.  This  thickening  has 
been  designated  as  the  parapostgenal  thickening,  while  the  area  mesad 
of  it  is  the  parapostgena  (ppo).  The  two  mesal  projections  of  the 
parocciput  on  the  lateral  margin  of  the  occipital  foramen  serve  as  points 
for  the  articulation  of  neck  sclerites  and  mark  the  ventral  boundary  of 
the  occiput. 

The  occipital  foramen  (o.  f )  is  centrally  situated  in  all  but  a  few 
genera,  such  as  Tipula  (Fig.  95),  Limnobia  (Fig.  93),  Psorophora  (Fig. 
96),  and  Bibio  (Fig.  92),  in  which  it  is  near  the  dorsal  margin.  The 
size  of  the  occipital  foramen  is  more  or  less  constant  thruout  the  order, 
but  in  Psj'choda  (Fig.  82)  and  Promachus  (Fig.  84)  it  is  comparatively 
much  larger  than  in  PipunciUus  (Fig.  106)  and  Exoprosopa  (Fig.  98). 
The  shape  of  the  occipital  foramen  varies  somewhat,  but  usually  it  is 
in  the  form  of  a  figure  eight.  The  constrictions  in  the  lateral  margins 
are  generally  due  to  the  mesal  projections  of  the  parocciput,  which 
vary  to  some  extent  in  their  situation.  The  projections  in  Exoprosopa 
(Fig.  98),  Pipunculus  (Fig.  106),  and  Mydas  (Fig.  99)  meet  on  the 
meson  and  completely  divide  the  occipital  foramen  into  two  openings. 
The  neck  sclerites  (n.  s)  always  articulate  with  these  mesal  projections 
and  are  represented  in  a  number  of  the  figures. 

The  occiput  (occ)  of  all  genera  figured  resembles  in  general  the 
occiput  of  the  hypothetical  head,  since  no  sutures  separate  the  vertex, 
the  occiput,  and  the  postgenae.  The  position  of  the  occipital  foramen 
and  the  contour  of  the  caudal  surface  determine  the  amount  of  variation 
in  the  occiput  as  well  as  in  the  postgenae.  In  some  genera,  Empis  (Fig. 
164)  and  Bibiocephala  (Fig.  156),  the  caudal  aspect  is  convex;  while 
in  others,  Exoprosopa  (Fig.  98)  and  Pipunculus  (Fig.  106),  it  is  de- 
cidedly concave.  Siiture-like  markings  or  depressions  are  present  near 
the  dorsal  margin  of  the  caudal  aspect  in  the  heads  of  Tabanus  (Fig. 
74),  Stratiomyia  (Fig.  104),  Bibio  (Fig.  91),  Bibiocephala  (Fig.  83), 
Leptis  (Fig.  103),  Psilocephala  (Fig.  100),  and  others.  These  depres- 
sions mark  the  place  of  contact  of  the  mesal  portions  of  the  ocular 
sclerites  with  the  head-capsule,  and  are  in  no  way  homologous  with  the 
sutures  about  the  occiput  in  generalized  insects. 

The  area  about  the  dorsal  and  lateral  margin  of  the  occipital  fora- 
men, the  parocciput  (pocc),  is  more  or  less  differentiated  from  the  re- 
mainder of  the  occiput  in  all  the  species  studied.  In  the  more  generalized 
forms,  Bibiocephala  (Fig.  S3),  Trichocera  (Fig.  78),  Tipula  (Fig.  95)^ 


195]  HEAD    OF  DIPTERA  —  PETERSOX  25 

Sciara  (Fig.  81),  and  Bittacomorpha  (Fig.  85),  it  is  only  a  thickened 
edge ;  but  in  a  large  nximber  of  species  thruout  the  order  it  is  a  clearly 
defined  piece,  set  off  from  the  occiput  proper  bj-  a  secondary  suture. 
The  indefiniteness  of  this  piece  in  a  large  number  of  the  generalized 
Diptera  and  the  want  of  an  homologous  part  in  generalized  insects 
support  the  view  that  it  is  only  a  secondary  modification  of  the  occiput. 

The  parocciput  (poce),  in  most  genera,  occurs  as  a  narrow  piece 
about  the  dorsal  and  lateral  margin  of  the  occipital  foramen,  and  its 
ventral  ends  project  mesad.  In  the  heads  of  the  Cyclorrhapha  thi-ee 
secondarily  developed,  chitinized  thickenings  (th)  arise  from  the  ental 
surface  of  the  parocciput;  two  of  these  project  dorso-laterad  from  the 
lateral  portions  of  the  parocciput,  and  the  third  is  on  the  meson.  These 
thickenings  are  also  present  in  some  of  the  Brachj-cera,  such  as  Dolieho- 
pus  (Fig.  112).  Their  greatest  development  is  found  in  Eristalis  (Fig. 
113),  where  two  dorso-lateral  thickenings  (th)  extend  to  the  caudal 
margins  of  the  compound  eyes  and  a  third  thickening,  on  the  meson, 
bifurcates  a  short  distance  dorsad  of  the  occipital  foramen,  the  two  arms 
connecting  with  the  dorso-mesal  angles  of  the  compound  eyes.  In  the 
genera  figured,  the  dorso-lateral  thickenings  are,  on  the  whole,  better 
developed  than  the  thickening  on  the  meson.  In  Thelaira  (Fig.  128) 
and  ilusca  (Fig.  133)  the  dorso-lateral  thickenings  project  dorsad  to 
the  margin  of  the  head.  The  area  included  between  them  is  called  by 
several  writers  the  epicephalon,  or  the  occiput;  and  tho  it  is  entirely 
different  in  origin  from  similarly  situated  areas  in  Tabanus  (Fig.  74) 
and  other  genera,  the  same  name  is  applied  in  the  different  cases.  These 
names  and  others  used  by  systematists  have  no  morphological  signifi- 
cance for  they  can  not  be  homologized  with  the  primary  selerites  of  a 
generalized  insect. 

The  postgenae  (po)  of  the  hypothetical  dipterous  head  have  been 
carefully  compared  with  those  of  the  heads  of  such  generalized  insects 
as  the  Orthoptera.  The  mesal  membranous  area  between  the  postgenae 
is  homologous  with  the  membrane  of  the  neck  and  with  the  membrane 
surrounding  the  proximal  ends  of  the  maxillae  and  the  labium.  There 
are  no  sutures  or  selerites  along  the  mesal  portions  of  the  postgenae  ia 
such  generalized  insects  as  the  Orthoptera ;  consequently  the  parapost- 
genae  (ppo)  described  above  can  not  be  homologous  with  any  primary 
sclerite.  In  Diptera  the  parapostgenae  are  undoubtedly  special  modi- 
fications of  the  postgenae. 

The  postgenae  and  the  parapostgenae  of  a  majority  of  the  Nematoc- 
era  resemble  those  of  the  hypothetical  head.  In  Chironomus  (Fig. 
88)  and  Trichocera  (Fig.  78)  the  parapostgenal  thickenings  are  want- 
ing.    The  invaginations  for  the  posterior  arms  of    the    tentorium    in 


26  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [196 

Simulium  (Fig.  77)  are  adjacent  to  the  occipital  foramen,  consequently 
the  parapostgenae  are  confined  to  the  lateral  margins  of  the  occipital 
foramen.  In  Tabanus  also  the  invaginations  are  adjacent  to  the  occipi- 
tal foramen,  and  the  postgenae  are  connected  ventrad  of  the  occipital 
foramen  in  the  male  and  by  a  narrow  strip  in  the  female. 

The  area  ventrad  of  the  occipital  foramen  is  a  continuous  ehitinized 
piece  in  all  of  the  Cyclorrhapha  and  the  Orthorrhapha.  There  is  only 
one  probable  explanation  of  the  origin  of  this  area.  It  has  been  derived 
from  the  fusion  of  the  mesal  margins  of  the  postgenae.  The  evidence 
for  this  interpretation  is  found  in  a  number  of  the  Nematocera.  The 
mesal  margins  of  the  postgenae  in  Trichocera  (Fig.  78)  and  Seiara 
(Fig.  81)  are  curved  mesad  and  in  some  cases  actually  join,  as  in  the 
female  of  Bibiocephala  (Fig.  83).  The  peculiar  elongated  heads  of 
Limnobia  (Fig.  93),  Tipula  (Fig.  95),  and  Psorophora  (Fig.  96)  show 
a  distinct  depressed  line  on  the  meson  along  wliich  the  postgenae  have 
joined.  In  a  number  of  the  genera  of  the  Orthorrhapha  and  the  Cy- 
clorrhapha the  ventral  margin  of  the  caudal  aspect  is  decidedly  concave. 
This  condition  may  be  due  to  a  former  stage  in  the  development  of  the 
fused  postgenae.  In  all  cases  where  the  area  ventrad  of  the  occipital 
foramen  is  ehitinized,  the  invaginations  of  the  posterior  arms  of  the 
tentorium  are  somewhat  adjacent  to  the  occipital  foramen  and  the 
attachments  of  the  maxillae  are  removed  to  or  beyond  the  ventral  mar- 
gin of  the  head.  Seiara  (Fig.  81)  is  a  good  example  of  an  early  stage 
in  the  development  of  the  above  relationship.  The  variations  in  the 
shape  and  extent  of  the  postgenae  and  the  parapostgenae  are  well  illus- 
trated by  the  figures. 

Tentorium. — There  is  present  within  the  head  of  generalized  insects 
a  definite  arrangement  of  ehitinized  rods  and  plate-like  structures  which 
go  to  support  the  internal  organs  and  furnish  places  for  the  attachment 
of  muscles.  These  rods  or  plates  arise  from  three  pairs  of  openings  on 
the  head  known  as  the  invaginations  of  the  anterior  arms,  dorsal  arms, 
and  posterior  arms  of  the  tentorium.  The  invaginations  of  the  anterior 
arms  are  usually  associated  with  the  lateral  margins  of  the  clypeus, 
with  one  of  the  points  of  articulation  of  the  mandibles,  and  frequently 
with  the  ventral  ends  of  the  arms  of  the  epicranial  suture.  The  invagi- 
nations of  the  dorsal  arms  are  associated  with  the  points  of  attachment 
of  the  antennae  and  near  the  dorsal  portions  of  the  arms  of  the  epi- 
cranial suture.  The  invaginations  of  the  posterior  arms  are  associated 
with  the  occipital  foramen  and  the  points  of  attachment  of  the  maxillae. 
The  three  pairs  of  arms  i:nite  within  the  head ;  the  small  dorsal  arms 
unite  with  the  larger  anterior  arms,  and  these,  in  turn,  join  with  the 
posterior  arms,  which  are  confined  to  the  caudal  portion  of  the  head- 


197]  HEAD    OF   DIPTERA—PETERSOX  27 

capsule.    The  free  euds  of  the  posterior  arms  are  fused  aud  form  the 
body  of  the  tentorium. 

The  tentorium  undergoes  a  considerable  amount  of  variation  in 
the  different  orders,  but  so  far  as  observed  the  above  associations  be- 
tween the  invaginations  and  the  fixed  and  movable  parts  of  the  head 
are  always  retained  by  the  more  generalized  members  of  each  order. 
This  is  also  true  for  a  generalized  hpothetieal  dipterous  head.  The 
tentorium  (t)  of  such  a  head  (Fig.  140  and  141)  is  considerably  modi- 
fied when  compared  with  the  tentorium  of  a  generalized  insect.  Two 
pairs  of  invaginations  are  present  on  the  cephalic  aspect  of  the  head 
(Fig.  1).  The  dorsal,  indistinct  pair  (i.  d),  just  ventrad  of  the  anten- 
nae, are  homologous  with  the  invaginations  of  the  dorsal  arms  of  the 
tentorium,  while  the  prominent  pair  (i.  a)  of  invaginations  ventrad  of 
these  and  located  in  the  arms  of  the  epicranial  suture  (a.  e.  s)  and 
adjacent  to  the  lateral  ends  of  the  fronto-clypeal  suture  are  the  invagi- 
nations of  the  anterior  arms  of  the  tentorium.  One  pair  of  invagina- 
tions (i.  p)  is  present  on  the  caudal  aspect  of  the  head-capsule  (Fig. 
73)  somewhat  ventrad  of  the  ventro-lateral  margins  of  the  occipital 
foramen.  These  are  the  invaginations  of  the  posterior  arms  of  the 
tentorium.  Each  lateral  half  of  the  tentorium  is  Y-shaped  (Fig.  141), 
the  stem  of  the  Y  arising  from  the  invaginations  on  the  caudal  aspect, 
its  caudal  portion  being  a  part  of  the  posterior  arms  (p.  a)  of  the  tento- 
rium. The  large  ventral  arm  of  the  Y  and  the  cephalic  portion  of  its 
stem,  constitute  the  anterior  arm  (a.  a),  and  the  small  dorsal  arm  of 
the  Y  is  the  dorsal  arm  (d.  a)  of  the  tentorium.  These  two  arms  con- 
nect with  their  respective  invaginations  on  the  cephalic  aspect.  The 
body  of  the  tentorium  (b.  t)  is  apparently  represented  by  a  small,  rudi- 
mentary, mesal  projection  arising  from  the  posterior  arms  near  the 
caudal  portion  of  the  stem  of  the  Y. 

The  association  between  the  movable  appendages  and  the  invagi- 
nations of  the  tentorium  is  discussed  under  the  respective  appendages. 
From  this  point,  the  tentorial  structures  as  they  occur  in  the  various 
genera  are  compared  with  the  hypothetical  type  and  the  line  of  speciali- 
zation noted.  The  forms  without  a  ptilinum  are  considered  first.  The 
parts  of  the  free  tentorium,  not  completely  fiised  with  the  head-capsule, 
are  indicated  in  the  figures  by  dotted  lines. 

The  tentorium  of  Tabanus  (Fig.  142  and  143)  is  generalized  and 
closely  resembles  the  hj-pothetical  type ;  consequently  it  furiiislies  a 
good  starting  point  for  a  discussion.  Two  pairs  of  invaginations  are 
present  on  the  cephalic  aspect  (Fig.  20)  ;  of  these  the  invaginations  for 
the  anterior  arms  (i.  a)  are  the  more  prominent.  The  dorsal  arms 
(i.  d)   arise  from  the  head-capsule  just  ventro-laterad  of  the  antennae 


28  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [198 

and  connect  with  the  arms  of  the  epicranial  suture  (a.  e.  s).  The  in- 
vaginations of  the  anterior  arms  are  situated  near  the  ventral  ends  of 
the  arms  of  the  epicranial  suture.  The  invaginations  on  each  lateral 
half  of  the  head  are  joined  together  by  the  arms  of  the  epicranial  suture 
and  resemble  the  hypothetical  type.  Two  pairs  of  invaginations  are  also 
present  on  the  cephalic  aspect  of  Simulium  (Fig.  2  and  3),  but  in  this 
genus  they  are  not  as  prominent  as  in  Tabanus.  They  are  situated  on 
the  vertex  (v),  adjacent  to  the  compound  eyes.  In  the  female  the  arms 
of  the  epicranial  suture  are  well  defined  and  the  invaginations  are 
closely  adjacent  to  them,  while  in  the  male  the  sutures  are  wanting. 
Tabanus  and  Simulium  are  the  only  forms  figured  which  show  two 
distinct  pairs  of  invaginations  on  the  cephalic  aspect.  All  other  genera 
have  only  one  pair  and  these  are  of  two  types.  They  are  either  long 
and  slit-like  or  they  resemble  small  pits  or  darkened  spots  on  the  ectal 
surface.  The  long  slit-like  invaginations  found  in  Leptis  (Fig.  35), 
Psilocephala  (Fig.  36),  Platypeza  (Fig.  32),  Seenopiniis  (Fig.  41), 
Exoprosopa  (Fig.  29),  Stratiomyia  (Fig.  27),  Mydas  (Fig.  30),  Erista- 
lis  (Fig.  25),  and  other  genera  have  a  special  significance  which  will 
be  more  fully  discussed  later.  The  small,  pit-like  invaginations  are 
present  in  the  Nematocera  and  in  Pipunculus  (Pig.  38)  and  Empis 
(Fig.  40).  These  are  situated  on  the  chitinized  area  of  the  vertex;  or 
on  the  fronto-clypeus,  adjacent  to  the  arms  of  the  epicranial  suture  and 
usually  close  to  the  compound  eyes.  Their  position  and  structure  indi- 
cate that  they  are  the  invaginations  of  the  anterior  arms  of  the  tento- 
rium. In  a  few  of  the  genera  of  the  Orthorrhapha  and  in  some  others, 
as  Lonchoptera  (Fig.  37),  Tipula  (Fig.  18),  and  Aphiochaeta  (Pig. 
31),  no  invaginations  are  present  on  the  cephalic  aspect  of  the  head. 

One  pair  of  invaginations,  that  for  the  posterior  arms  (i.  p)  of 
the  tentorium,  is  present  on  the  caudal  aspect  of  the  heads  of  all  genera 
examined  except  Oncodes  (Pig.  105),  Olfersia  (Fig.  139),  Tipula  (Pig. 
95),  and  perhaps  a  few  species  of  other  genera  in  which  it  is  difScult 
to  be  sure  of  their  presence.  These  invaginations  in  Bibioeephala  (Fig. 
83),  Trichocera  (Fig.  76),  Dixa  (Fig.  79),  Ehyphus  (Pig.  80),  Sciara 
(Fig.  81),  Psychoda  (Fig.  82),  Rhabdophaga  (Fig.  86),  Chironomus 
(Fig.  88),  Bittacomorpha  (Fig.  85),  Mycetophila  (Fig.  87),  and  Myce- 
tobia  (Fig.  90)  are  decidedly  ventrad  of  the  occipital  foramen  and 
adjacent  to  the  proximal  ends  of  the  maxillae.  They  are  connected 
with  the  lateral  margins  of  the  occipital  foramen  by  means  of  the  para- 
postgenal  thickenings  except  in  Chironomus  and  Trichocera.  The  above- 
named  forms  closely  resemble  the  hypothetical  type.  In  a  few  genera 
of  the  Nematocera,  such  as  Psorophora  (Fig.  96)  and  Simulium  (Fig. 
77),   the  invaginations  are   adjacent  to  the   occipital  foramen.     This 


199]  HEAD    OF  DIPTERA— PETERSON  29 

position  is  characteristic  of  these  invaginations  in  the  Brachycera,  and 
the  figures  show  the  details  of  the  variations  in  the  position  of  the 
invaginations  on  the  posterior  arms  of  the  tentorium. 

Two  lines  of  specialization  appear  in  the  tentorium  of  the  Diptera, 
one  in  the  reduction  of  the  dorsal  arms  and  the  other  in  the  union  of  the 
dorsal  arms  with  the  anterior  arms.  The  two  tj-pes  of  invaginations 
described  for  the  cephalic  aspect  of  the  head  bear  directly  upon  this 
problem.  The  most  important  evidence  in  proof  of  these  two  types  of 
development  is  found  in  the  structure  of  the  arms. 

In  Sciara  (Fig.  150),  Bibio  (Fig.  153  and  154),  Psorophora  (Fig. 
159),  Trichocera  (Fig.  158),  Bibiocephala  (Fig.  155),  Dixa  (Fig.  163), 
and  others,  two  long  narrow  rods  extend  on  each  side  between  the 
invaginations  on  the  caudal  aspect  and  the  invaginations  on  the  cephalic 
aspect.  These  rods  are  composed  of  the  posterior  arms  (p.  a)  and  the 
anterior  arms  (a.  a)  of  the  tentorium.  The  dorsal  arms  are  completely 
reduced  in  these  forms.  Other  genera  show  completely  developed  dorsal 
arms  or  rudiments  of  the  same.  The  dorsal  arms  (d.  a)  are  distinct 
and  free  in  Pipunculus  (Fig.  151).  They  arise  from  the  anterior  arms 
and  project  eephalad  to  the  cephalic  aspect  of  the  head,  where  thej'- 
connect  with  small  but  distinct  ental  projections  adjacent  to  the  anten- 
nae. The  cephalic  ends  of  the  dorsal  arms  are  very  delicate  and  easily 
broken  in  dissecting.  There  are  no  invaginations  on  the  ectal  surface. 
In  Chironomus  (Fig.  152)  the  tentorial  arms  are  swollen  near  the  mid- 
dle of  their  length,  and  the  distinct  humps  on  the  dorsal  side  are 
interpreted  as  rudiments  of  the  dorsal  arms.  Promachus  (Fig.  147) 
has  two  long,  free,  finger-like  projections,  arising  from  the  ocular 
sclerite  near  the  antennae,  which  project  toward  the  tentorium  proper. 
These  projections  are  apparently  dorsal  arms  of  the  tentorium,  or 
derivatives  of  the  same  that  have  retained  their  connection  with  the 
ocular  sclerite  near  the  mesal  margin  of  the  compound  eye  but  have  lost 
their  connection  with  the  tentorium  proper.  A  similar  relationship 
exists  between  the  dorsal  arms  and  the  ocular  sclerite  in  Tabanus  (Fig. 
22).  If  the  above  structures  in  Promachus  are  dorsal  arms,  then  the 
anterior  arms  are  large  (Fig.  148)  and  the  slit-like  invaginations  on  the 
cephalic  aspect  are  only  the  invaginations  of  the  anterior  arms  of  the 
tentorium. 

The  tentoria  of  the  Nematocera  above  described  are  in  the  ventral 
half  of  the  head-cavity  and  their  situation  is  dependent  upon  the  posi- 
tion of  the  invaginations.  Usually  the  invaginations  of  the  anterior 
arms  are  ventrad  of  the  invaginations  of  the  posterior  arms ;  but  Bibio- 
cephala (Fig.  155)  is  an  exception  to  this  rule  if  the  tentorium  in  this 
genus  is  composed  of  only  the  anterior  and  posterior  arms — and  there 


30  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [200 

is  no  evidence  to  the  contrary.  In  some  genera,  as  in  Lonchoptera 
(Fig.  177),  Rhabdopliaga  (Pig.  170),  and  Empis  (Fig.  164),  the  tento- 
ria  are  not  free  rods  extending  thru  the  head  cavity,  but  are  completely 
united  with  the  ventral  margin  of  the  head,  or  nearly  so.  The  tentorium 
of  Aphiochaeta  (Fig.  174)  is  reduced  to  two  small  ental  projections 
adjacent  to  the  occipital  foramen,  while  in  Tipula  (Fig.  178)  the  ten- 
torium is  apparently  wanting. 

In  a  majority  of  the  Brachycera  the  tentorial  arms  are  specialized 
by  fusion,  and  Tabanus  (Fig.  143)  illustrates  an  early  stage  in  this 
development.  The  principal  difference  between  the  tentorium  of  Taba- 
nus and  the  hypothetical  type  is  the  presence  of  a  thin  chitinized  plate 
in  the  V-shaped  opening  between  the  anterior  and  dorsal  arms.  Simu- 
lium  (Fig.  144),  of  the  Nematocera,  has  a  similar  plate,  and  these  two 
genera  clearly  demonstrate  the  first  stage  in  the  fusion  of  these  two 
arms.  The  cephalic  end  of  the  tentorium  in  My  das  (Fig.  146),  Leptis 
(Fig.  145),  Scenopinus  (Fig.  149),  and  Exoprosopa  (Fig.  162)  is  a 
broad  uniformly  chitinized  triangular  area.  This  condition  is  accounted 
for  on  the  basis  of  the  union  of  the  anterior  and  dorsal  arms.  The 
invaginations  on  the  cephalic  aspect  of  these  forms  agree  in  all  respects 
with  this  interpretation.  In  Tabanus  (Fig.  20)  the  invaginations  on 
each  side  are  joined  together  by  the  epicranial  siiture,  while  in  the 
above  forms  the  invaginations  are  slit-like  and  occupy  the  greater  part 
of  the  arms  of  the  epicranial  suture.  The  slit-like  invaginations  are 
easily  explained  if  the  anterior  and  dorsal  arms  are  considered  as  united. 

The  posterior  arms  of  the  tentoria  of  the  Nematocera  and  the 
Brachycera  vary  in  shape,  size,  and  location.  The  anterior  and  posterior 
arms  are  united  within  the  head  and  no  sharp  line  can  be  drawn  be- 
tween them.  The  body  of  the  tentorium  (b.  t)  is  represented  by  small 
projections  on  the  mesal  surface  of  the  posterior  arms  of  most  genera. 

Many  interesting  features  occur  in  the  modifications  of  the  tentoria 
of  this  group.  In  Dolichopus  (Fig.  43  and  168)  it  appears  to  be  fused 
with  the  dorsal  margin  of  the  slit-like  openings  on  each  side  between 
the  mesal  margin  of  the  compound  eye  and  the  fronto-clypeus.  The 
tentorium  of  Mydas  (Fig.  146)  is  large  and  tubular,  and  it  is  possible 
to  push  a  good-sized  needle  thru  the  opening  on  the  cephalic  aspect  to 
the  opening  of  the  posterior  arms  on  the  caudal  aspect. 

The  tentoria  of  the  genera  possessing  a  ptilinum  differ  principally 
from  the  foregoing  in  the  degree  of  fusion  with  the  head-capsule.  In 
most  genera  of  this  group  the  tentorium  is  completely  united  with  the 
head,  but  in  a  number  of  the  Aealyptratae  the  tentorial  arms  arise  as 
free  rods  from  the  invaginations  on  the  caudal  aspect  and  project  to 
the  latero-ventral  margins  of  the  head-capsule,  with  which  they  unite 


201]  HEAD    OF  DIPTERA  — PETERSON  31 

and  continue  cephalad  as  thickenings  adjacent  to  the  ventral  margin 
of  the  head,  as  in  Sapromj'za  (Fig.  171),  Loxoeera  (Fig.  169),  Euaresta 
(Fig.  175),  Calobata  (Fig.  183),  Chrysomyza  (Fig.  181),  Drosophila 
(Fig.  172),  Chyromya  (Fig.  179),  Heteroncura  (Pig.  176),  and  Teta- 
nocera  (Fig.  180).  In  those  forms  where  the  tentorium  is  completely 
fused  with  the  head,  as  in  Sepsis  (Fig.  184),  Chloropisca  (Fig.  189), 
Coelopa  (Fig.  182),  and  Borborus  (Fig.  188),  it  is  a  continuous  thick- 
ening from  the  latero-ventral  angle  of  the  occipital  foramen  to  the 
cephalo-ventral  aspect  of  the  head-capsule.  The  tentorium  between  the 
invaginations  for  the  posterior  arms  and  the  ventro-lateral  margins  of 
the  head-eapsule  is  apparently  wanting  in  Musca  (Fig.  194),  Thelaira 
(Fig.  196),  Arehytas  (Fig.  197),  and  some  other  genera;  in  one  or 
two  cases  it  is  possible  to  trace  a  faint  mark  which  would  indicate  the 
line  of  connection.  The  tentoria  of  some  of  the  genera  of  the  Acalyp- 
tratae  and  the  Calyptratae  show  an  iinusual  development  of  the  tento- 
rial thickenings  (t.  th)  in  that  they  extend  about  the  entire  caudal  part 
of  the  ventral  margin  of  the  head.  In  some  cases  these  tentorial  thick- 
enings reach  the  occipital  foramen,  as  in  Calobata  (Fig.  114),  Scatoph- 
aga  (Fig.  135),  Heteroneura  (Fig.  126),  Lispa  (Fig.  116),  and  Mj-ios- 
pila  (Fig.  120),  while  in  Musca  (Fig.  133),  Coelopa  (Fig.  121), 
Hydrotaea  (Fig.  127),  and  other  genera,  there  is  no  such  connection. 

The  invaginations  of  the  posterior  arms  of  the  tentorium  of  the 
Acalj-ptratae  and  the  Calyptratae  are  situated  laterad  or  latero-ventrad 
of,  and  adjacent  to,  the  occipital  foramen.  In  many  of  the  species 
figured  the  invaginations  are  merely  long,  heavily  chitinized  furrows 
extending  latero-ventrad  from  the  occipital  foramen,  and  very  often 
it  is  difficult  to  locate  them  definitely. 

Two  mesal  projections  arise  from  the  proximal  portions  of  the 
posterior  arms  in  a  majority  of  the  Cyelorrhapha.  In  some  species 
these  structures  are  well  developed,  and  their  mesal  ends  apparently 
join  on  the  meson,  cephalad  of  the  occipital  foramen.  These  structures 
are  similar  to  those  described  for  the  Brachycera  and  are  rudiments  of 
the  body  of  the  tentorium. 

No  invaginations  of  the  tentorium  occur  on  the  cephalic  aspect  in 
any  of  the  forms  which  possess  a  ptilinum.  On  account  of  the  decided 
specialization  of  this  aspect,  it  is  very  difficult  to  know  just  what  has 
happened.  The  tentorium  is  represented  by  thickenings  which  extend 
from  the  ventral  to  the  cephalic  aspect  of  the  head.  The  extent  of 
these  thickenings  varies;  in  some  genera  they  continue  to  the  antennal 
fossae,  while  in  others  they  are  practically  wanting. 


32  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [202 


MOVABLE  PARTS  OF  THE  HEAD 

In  arrangement  and  structure  the  movable  parts  of  the  head  of 
the  generalized  Diptera  are  homologous  with  the  movable  appendages 
of  other  generalized  insects.  In  the  Cyelorrhapha  the  parts  retain  their 
relative  position,  but  structurally  they  undergo  striking  modifications 
and  in  some  cases  almost  complete  reduction. 

To  make  clear  the  use  of  a  number  of  terms  found  in  the  following 
discussions,  the  mouth-parts  as  a  whole  will  be  considered  at  this  point. 
The  appendages  of  the  mouth  of  the  generalized  Diptera  are  free,  inde- 
pendent structures,  with  their  proximal  ends  adjacent  to  the  head-cap- 
sule. The  cardines  and  stipites  of  the  maxillae  ai-e  exceptions  to  the 
above  statement,  in  that  they  are  embedtled  in  the  mesal  membranous 
area  of  the  caudal  aspect  of  the  head.  The  mouth-parts,  the  labrum- 
epipharynx,  and  the  hypopharynx  constitute  in  the  Calyptratae  a  single 
complex  mouth-appendage  designated  as  the  proboscis.  The  chitinized 
parts  of  the  jDroboscis  are  far  removed  from  the  head-capsule,  but  in 
this  projection  of  the  parts,  the  proximal  ends  of  the  chitinized  ap- 
pendages are  joined  together  and  have  the  same  relationship  with  each 
other  as  in  generalized  insects. 

The  term  proboscis  is  most  applicable  among  the  Cyelorrhapha  to 
those  whose  mouth-parts  resemble  those  of  Musca.  The  proboscis  is 
naturally  divided  into  three  areas  by  the  two  bends  which  it  makes  as 
it  is  withdrawn  into  the  oral  cavity.  Tlie  parts  of  the  proboscis  have 
beeu  given  varied  and  confusing  names.  Hewitt  divides  it  into  two 
general  areas — the  rostrum  and  the  proboscis  proper.  He  says :  ' '  The 
proboscis  consists  of  two  parts,  a  proximal  membranous  conical  por- 
tion, the  rostrum,  and  a  distal  half,  the  proboscis  proper,  which  bears 
the  oral  lobes.  The  term  haustellum  is  also  used  for  this  distal  half 
(minus  the  oral  lobes)  and  as  a  name  it  is  probably  more  convenient, 
as  the  term  proboscis  is  used  for  the  whole  structure, — rostrum,  haustel- 
lum and  oral  lobes". 

The  terms  rostrum  and  haustellum  have  been  used  in  various  ways 
by  numerous  workers  in  diilerent  orders;  consequently  the  parts  which 
they  designate  are  by  no  means  homologous.  A  more  comprehensive 
set  of  terms  based  upon  the  word  proboscis  has  been  used  by  a  few 
workers,  who  divide  the  proboscis  into  basiproboscis,  mediproboscis,  and 


203]  HEAD    OF  DIPTERA— PETERSON  33 

distiproboscis.  These  terms  have  here  been  adopted.  The  basiproboscis 
(bpr)  is  equivalent  to  the  rostrum,  and  may  be  defined  as  the  mem- 
branous, cone-shaped  area  between  the  ventral  margin  of  the  head- 
capsule  and  the  proximal  end  of  the  theca.  The  tormae,  labrum- 
epipharynx,  hypopharynx,  and  maxillae  are  parts  of  the  basiproboscis. 
The  mediproboscis  (mpr)  is  the  median  section  of  the  proboscis  and 
includes  the  theca  and  the  ehitinized  cephalic  groove  of  the  labium.  It 
is  equivalent  to  the  haustellum  of  most  authors.  The  distiproboscis 
(dpr),  the  enlarged  dilated  lobes  at  the  distal  end  of  the  proboscis,  is 
composed  of  the  paraglossae,  with  their  pseudotracheal  areas,  and  the 
glossae.  The  distiproboscis  is  equivalent  to  the  oral  lobes,  or  labellae. 
The  movable  appendages  of  the  head  are  discussed  in  the  following 
order:  antennae,  mandibles,  maxillae,  and  labium. 

Antennae. — The  antenna  of  a  generalized  hypothetical  dipterous 
head  (Fig.  199h)  is  many-segmented  and  of  a  filiform  type.  All  the 
segments  are  similar  excepting  the  two  large  proximal  ones  known  as 
the  scape  (sc)  and  the  pedicel  (pd).  The  scape  articulates  with  the 
ehitinized  antennal  sclerite  (a.  s)  which  bounds  the  periphery  of  the 
antennal  fossa  (a.  f )  that  is  situated  on  the  vertex  dorsad  of  the  arms 
of  the  epicranial  suture.  The  antennae  of  the  hypothetical  type  resem- 
ble the  antennae  of  many  generalized  insects. 

The  antennae  of  a  majority  of  the  Nematocera  resemble  the  hypo- 
thetical type,  and  on  the  whole  resemble  each  other.  The  variations  in 
shape  and  size  can  be  seen  in  the  figures.  Seeoudai'y  sexual  variation 
occurs  in  a  few  of  the  Nematocera,  in  which  the  antennae  of  the  male, 
illustrated  by  Chironomus  (Fig.  207)  and  Psorophora  (Fig.  211),  bear 
long  flexible  setae  while  those  of  the  female  are  almost  bare. 

The  antennae  of  the  Brachycera  show  a  wide  range  of  development, 
but  in  a  majority  of  the  genera  figured  the  main  line  of  specialization 
is  toward  the  type  found  in  Lonchoptera  (Fig.  223)  and  Dolichopus 
(Fig.  226).  One  of  the  striking  exceptions  to  this  general  line  of  de- 
velopment occurs  in  the  geniculate  type  found  in  Stratiomyia  (Fig. 
213).  The  antennae  of  the  Brachycera  have,  as  a  ride,  fewer  segments 
than  the  Nematocera.  The  scape  and  pedicel  undergo  only  a  slight 
change,  in  this  group,  but  the  flageUum  (fl)  is  greatly  modified.  The 
proximal  segment  of  the  flagellum,  or  the  third  segment  of  the  antenna, 
is  enlarged,  while  the  remaining  segments  are  so  reduced  in  size  as  to 
resemble  the  lash  of  a  whip.  The  lash-like  portion  of  the  antenna  is 
called  the  arista  (ar).  The  following  genera  suggest  the  various  stages 
thru  which  the  antennae  have  passed  in  attaining  the  museid  type  of 
development.  In  Tabanus  (Fig.  214),  Empis  (Fig.  215),  Exoprosopa 
(Fig.  216),  Promachus  (Fig.  217),  and  Leptis  (Fig.  218)  the  flagellum 


34  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [204 

is  stylate,  and  the  third  segment  is  large  and  conical,  with  one  or  more 
segments  at  its  distal  end.  The  antennae  of  Platypeza  (Fig.  222), 
Lonchoptera  (Fig.  223),  Aphiochaeta  (Fig.  224),  Oecothea  (Fig.  227), 
and  Dolichopns  (Fig.  226)  show  an  advanced  stage  of  development  in 
which  the  third  segment  is  large  and  round  and  the  remaining  segments 
are  lash-like  and  situated  toward  one  side  of  the  third  segment.  All 
but  a  few  of  the  antennae  of  the  Cyclorrhapha  have  apparently  devel- 
oped from  a  type  similar  to  the  last-mentioned  genera.  The  principal 
differences  between  the  antennae  of  this  group  are  in  the  length  and 
breadth  of  the  third  segment  and  in  the  modification  of  the  arista.  The 
antennae  of  Olfersia  (Fig.  249)  are  of  a  reduced  museid  type,  and  are 
inserted  in  deep  cavities  on  the  cephalic  asjject  of  the  head ;  the  scape 
and  pedicel  are  greatly  reduced,  and  the  arista  is  merely  a  small  pro- 
jection on  the  lateral  aspect  of  the  large  segment. 

Antennal  sclerites  (a.  s)  are  present  only  in  Chironomus  (Fig.  12 
and  206)  and  Psorophora  (Fig.  10  and  26).  In  these  genera  it  is  a 
distinct  chitinized  ring  about  the  proximal  end  of  the  scape.  The  extent 
and  place  of  the  membrane  with  which  the  antennae  are  connected 
vary  considerably.  In  Trichocera  (Fig.  16),  Chironomus  (Fig.  12), 
Psorophora  (Fig.  26),  Mycetobia  (Fig.  7),  and  some  other  genera  it  is 
very  extensive. 

A  general  survey  of  the  antennae  of  the  Diptera  shows  that  in  the 
Nematocera  they  are  generalized  and  on  the  whole  resemble  each  other. 
The  specialized  antennae  of  the  Cyclorrhapha  in  all  but  a  very  few 
genera  are  of  a  museid  typ^,  and  also  quite  similar  in  form.  The 
antennae  of  the  Brachycera  present  a  few  specialized  types,  but  the 
majority  of  them  show  intermediate  stages  between  the  forms  found 
in  the  Nematocera  and  those  of  the  Cyclorrhapha. 

Mandibles. — Only  a  few  of  the  generalized  Diptera  possess  mandi- 
bles. They  are  present  in  the  females  of  Simulium  (Fig.  2  and  250), 
Tabanus  (Fig.  255  and  317),  Psorophora  (Fig.  159  and  251),  Cidicoides 
(Fig.  253),  Dixa  (Fig.  254),  and  Bibiocephala  (Fig.  155  and  256),  but 
wanting  in  the  males  of  all  the  species  examined  except  Simulium  (Fig. 
3  and  252).  The  males  of  Simulium  johannseni  and  S.  jenningsi  have 
distinct  mandibles.  No  other  males  of  Simulium  were  examined.  So 
far  as  known  this  is  the  first  record  of  a  male  dipteron  possessing  true 
mandibles. 

The  hypothetical  mandibles  (Fig.  256h)  of  a  dipteron  are  long, 
thin,  sword-shaped  structures  fitted  for  piercing.  They  thus  resemble 
the  mandibles  (md)  of  Tabanus  (Fig.  255)  and  Culicoides  (Fig.  253). 
They  are  situated  between  the  clypeus,  labrum-epipharynx,  and  max- 
illae, and  are  closely  associated  with  the  invaginations  of  the  anterior 


205]  HEAD    OF  DIPTERA— PETERSON  35 

arms  of  the  tentorium.  Structurally  the  hypothetical  mandibles  do  not 
resemble  the  biting  mandibles  of  the  Orthoptera,  but  their  situation 
and  their  association  with  the  invaginations  of  the  anterior  arms  of  the 
tentorium  are  the  same,  which  is  far  more  important  in  determining 
their  homology'  than  any  particular  form  thej'  may  assume. 

The  mandibles  vary  in  their  structure.  In  Psorophora  (Pig.  251) 
they  are  long  and  needle-like,  while  in  Tabanus,  Culicoides,  and  the 
male  of  Simulium  (Fig.  252)  they  are  sword-shaped,  and  in  Dixa  (Fig. 
254)  spindle-like.  The  mandibles  in  the  females  of  all  species  of  Simu- 
lium (Fig.  250)  examined  are  a  trifle  longer  than  those  in  the  males 
(Fig.  252)  and  much  broader  at  their  distal  ends.  The  greatest  spe- 
cialization in  structure  and  point  of  attachment  with  the  head  occurs 
in  the  long,  thin,  saw-like  mandibles  of  Bibiocephala  (Fig.  256)  and 
Blepharocera.  In  these  forms  they  are  longer  than  the  labium,  blunt 
at  the  end,  and  toothed  along  the  mesal  margin,  fitting  against  a  similar 
edge  on  the  lateral  margin  of  the  hypopharynx. 

All  mandibles  (md)  of  the  Diptera  are  connected  with  the  head- 
capsule  cephalad  of  the  maxillae  (mx)  and  caudad  of  the  labrum- 
epipharynx  (1.  ep)  and  the  fronto-cljijeus  (fr.  c).  In  this  respect  they 
resemble  the  hypothetical  type.  In  Psorophora,  Dixa,  Simulium,  and 
Tabanus  they  are  associated  with  the  invaginations  of  the  anterior  arms 
of  the  tentorium.  The  proximal  ends  of  the  mandibles  of  Psorophora 
(Fig.  159)  are  bent  cephalad,  and  articulate  with  the  head-capsule  at 
the  distal  ends  of  the  crescent-shaped  tentorial  thickenings  (t.  th)  which 
arise  from  the  margins  of  the  invaginations  of  the  anterior  arms  of  the 
tentorium.  In  Dixa  (Fig.  254)  the  mandibles  connect  with  the  head- 
capsule  at  the  ventro-caudal  angles  of  the  elypeus.  An  indistinct  thick- 
ening extends  dorsad  from  the  point  of  articulation  of  each  of  the  man- 
dibles toward  the  invaginations  of  the  anterior  arms  of  the  tentorium. 
The  mandibles  of  Simulium  (Fig.  250  and  252)  and  Tabanus  (Fig. 
317)  connect  with  the  head-capsule  directly  ventrad  of  the  invagina- 
tions of  the  anterior  arms  of  the  tentorium,  but  no  direct  connection 
occurs  between  them.  In  the  female  of  Simulium  the  mandibles  artic- 
ulate -n-ith  a  hook-shaped  projection  of  the  vertex.  The  mandibles  of 
Tabanus  (Fig.  255)  are  bifurcate  at  their  proximal  end  and  the  lateral 
bifurcation  articulates  with  the  liead.  The  location  of  the  mandibles  of 
Bibiocephala  (Fig.  155)  and  Blepharocera  is  generalized  with  respect 
to  their  position  between  the  maxillae  and  the  fronto-clj-peus,  but  their 
point  of  attachment  with  the  head-capsule  is  decidedly  specialized. 
They  unite  with  chitinized  pillars  (Fig.  83)  on  the  caudal  aspect 
ventro-laterad  of  the  invaginations  of  the  posterior  arms  of  the  tento- 
rium.   The  proximal  portion  of  eacb  mandible  is  a  long  chitinized  strip 


36  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [206- 

embedded  in  the  membrane.  These  strips  extend  cephalad  from  their 
caudal  connection  to  the  cephalic  margin  of  the  membrane  about  the 
mouth-parts.  At  this  point,  M'here  distinct  tendons  are  attached,  they 
turn  abruptly  ventrad  and  become  free  appendages.  All  connection 
between  the  mandibles  and  the  invaginations  of  the  anterior  arms  of 
the  tentorium  is  lost.  The  relationship  between  the  tentorium  and  the 
mandibles  has  not  been  observed  in  Culicoides  for  the  lack  of  material. 
No  other  families  of  the  Diptera  outside  of  those  to  which  the  above- 
named  genera  belong,  so  far  as  observed,  possess  true  mandibles  or 
rudiments  of  the  same.  When  mandibles  are  present,  they  are  always 
of  considerable  size  and  probably  functional. 

A  number  of  investigators  have  described  mandibles  for  many 
species  not  included  in  the  above  families.  Langhoffer  (1901)  describes 
mandibles  for  the  Dolichopodidae  which  are  shown  in  this  paper  to  be 
modifications  of  the  epipharynx  (Fig.  524  and  .528).  The  apodemes 
of  tlie  muscids  (Fig.  304,  308,  and  others)  have  been  called  mandibular 
tendons  by  MacCloskie  and  others.  This  is  incorrect  as  shown  by  the 
figures  and  in  the  discussion  of  the  maxillae.  A  number  of  workers 
(e.g.,  Wesche,  1909)  believe  that  the  mandibles  have  united  with  the 
labium  and  exist  as  chitinized  strips  on  the  cephalic  aspect  of  the 
labium  or  as  thickenings  on  the  meson  of  the  theca.  Neither  of  these 
interpretations  can  be  accepted  when  one  takes  into  consideration  the 
relative  position  of  these  so-called  mandibles  and  the  manner  of  devel- 
opment of  the  proboscis  of  the  Calyptratae.  The  chitinized  thickenings 
on  the  cephalic  aspect  of  the  labium  are  located  caudad  of  the  maxillae 
and  the  liypopharynx.  This  does  not  agree  with  the  position  of  the 
mandibles  of  other  insects.  Furthermore,  these  thickenings  are  present 
in  Tabanus  where  true  mandibles  occur.  The  chitinized  thickenings 
on  the  meson  of  the  theca  in  some  of  the  Diptera  can  not  be  considered 
as  rudiments  of  mandibles  for  many  reasons.  The  most  conclusive 
objection  to  tliis  interpretation  lies  in  the  fact  that  these  thickenings 
are  very  prominent  in  Simulium  which  has  distinct  mandibles  in  both 
sexes. 

When  interpreting  mouth-appendages,  it  is  always  necessary  to 
take  into  consideration  the  generalized  relationship  between  the  mouth- 
parts  and  their  association  with  the  invaginations  of  the  tentorium. 
It  is  also  very  desirable  to  observe  a  large  series  of  forms  before  attempt- 
ing to  homologize  the  parts.  The  above  interpretations  were  apparently 
not  made  from  either  of  tliese  vantage-points. 

Maxillae. — All  Diptera  having  functional  mouth-parts  have  max- 
illae. They  are,  however,  greatly  reduced  and  modified  in  some  genera,, 
and  at  first  glance  bear  little  or  no  relation  to  the  structure  or  location 


207]  HEAD    OF   DIPTERA  —  PETERSOX  37 

of  the  maxillae  of  generalized  Diptera  or  other  insects.  Numerous 
intermediate  stages  of  masillar}-  development  are  present  in  the  various 
species;  consequently  it  is  possible,  and  in  fact  comparativelj'  easy,  to 
trace  thruout  the  order  the  main  line  of  specialization  and  several  side 
lines. 

The  hypothetical  maxillae  of  the  Diptera  (Fig.  257)  resemble  the 
maxillae  of  a  generalized  insect  in  their  homologous  sclerites,  their  posi- 
tion between  the  mandibles  and  the  labium,  and  their  close  association 
with  the  invaginations  of  the  posterior  arms  of  the  tentorium.  Struc- 
turallj'  they  are  composed  of  small  triangular  cardines  (ca),  long 
stipites  (st),  five-segmented  palpi  (mx.pl),  needle-like  galeae  (g),  and 
short  laciniae  (la).  The  cardines  and  stipites  differ  from  those  of  gen- 
eralized insects  in  that  they  are  embedded  in  the  mesal  membranous 
area  ventrad  of  the  occipital  foramen.  The  palpi,  galeae,  and  laciniae 
are  free  appendages.  The  proximal  ends  of  the  cai'dines  are  adjacent 
to  the  invaginations  of  the  posterior  arms  of  the  tentorium.  The  struc- 
ture and  position  of  the  various  parts  of  the  hypothetical  type  have 
been  traced  thruout  the  order.  The  species  in  which  the  ptilinum  is 
wanting  are  considered  first. 

The  cardines  (ca)  are  small  distinct  triangular  selerites  in  Trichoc- 
era  (Fig.  260),  Rhyphus  (Fig.  261),  Dixa  (Fig.  262),  and  the  female 
of  Tabanus  (Fig.  259).  In  these  genera  they  are  adjacent  to  the  invagi- 
nations of  the  posterior  arms  of  the  tentorium.  The  cardines  of  Simu- 
lium  (Fig.  258),  in  both  males  and  females,  differ  from  those  of  the 
above  genera  in  that  thej'  are  large  and  occupy  nearly  all  of  the  mem- 
branous area  between  the  postgenae  dorsad  of  the  stipites.  Their 
margins  are  also  somewhat  indistinct.  No  other  forms  figured  have 
distinct  sclerites  that  are  homologous  with  the  cardines  of  the  hypo- 
thetical type.  The  maxillae  of  Rhabdophaga  (Fig.  268),  Bibiocephala 
(Fig.  269),  and  Chironomus  (Fig.  270)  connect  with  the  invaginations 
of  the  posterior  arms  by  means  of  narrow  chitinized  processes  which 
arise  from  the  stipites  proper.  Undoubtedly  these  pieces  are  reduced 
cardines  which  have  lost  the  suture  that  separates  them  from  the 
stipites.  The  presence  of  this  suture  is  suggested  by  the  suture-like 
depression  in  the  male  of  Bibioeepluila  (Fig.  76).  Excepting  Promachus 
(Fig.  276)  and  the  above  forms,  the  cardo  is  wanting  in  all  the  maxillae 
figured.  The  maxillae  of  Psychoda  (Fig.  263)  and  Sciara  (Fig.  267) 
closely  resemble  some  of  the  above  maxillae,  but  the  cardines  as  chi- 
tinized pieces  are  apparently  wanting.  There  is  a  distinct  membranous 
area  between  the  proximal  ends  of  the  stipites  and  the  invaginations 
of  the  posterior  arms  of  the  tentorium.  From  forms  such  as  these  it  is 
concluded  that  tlie  cardines  have  been  lost  as  chitiidzed  areas.  No 
other  interpretation  seems  possible  with  the  evidence  at  hand. 


38  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [208 

The  stipites  (st)  are  of  various  shapes  and  sizes  as  can  be  seen  in 
the  figures.  In  Rhabdophaga  (Pig.  268),  Bibiocephala  (Fig.  269), 
Chironomus  (Fig.  270),  and  possibly  Mycetobia  (Fig.  90),  they  have 
united  to  form  a  chitinized  strip  or  plate  in  the  membranous  area  dorsad 
of  the  labium.  This  piece  should  not  be  confused  with  the  submeutum 
of  the  labium.  In  all  species  in  which  the  postgenae  have  not  united 
ventrad  of  the  occipital  foramen,  the  proximal  ends  of  the  stipites  are 
near  the  invaginations  of  the  posterior  arms  of  the  tentorium.  In  all 
species  where  the  postgenae  form  a  continuous  plate,  the  stipites  are 
reduced  in  size  and  situated  at  or  beyond  the  ventral  margin  of  the 
head,  as  in  Mydas  (Fig.  319)  and  Eristalis  (Fig.  328).  In  other  words, 
the  usual  association  between  the  maxiUae  and  the  invaginations  of  the 
posterior  arms  has  been  lost.  Psilocephala  (Fig.  281)  and  Psorophora 
(Fig.  96)  are  exceptions  to  the  last  statement.  In  Psilocephala  chi- 
tinized thickenings  (ch.  th)  are  present  on  the  ental  surface  of  the 
postgenae  ventrad  of  the  occipital  foramen,  and  these  are  undoubtedly 
rudiments  of  the  stipites.  The  stipites  of  Psorophora  (Fig.  266  and 
96)  are  long,  free  rod-like  structures  located  entad  of  the  postgenae. 
They  extend  between  the  occipital  foramen  and  the  ventral  margin  of 
the  head.  The  stipites  of  Geranomyia  (Pig.  382)  and  Limnobia  (Fig. 
386)  are  also  entad  of  the  postgenae.  In  these  genera  their  proximal 
ends  are  united  and  they  have  no  connection  with  the  head-capsule. 
The  stipites  of  Tipula  (Fig.  277)  resemble  those  of  Geranomyia  and 
Limnobia,  but  there  is  greater  reduction  in  size,  and  they  are  completely 
united  along  their  mesal  margins,  thus  forming  a  single  median  piece. 

The  maxillae  of  Promachus  (Fig.  84)  differ  from  those  of  all  other 
genera  in  that  the  stipites  and  the  cardines  are  united  on  the  meson 
and  continuous  with  the  postgenae  near  the  occipital  foramen.  Narrow 
membranous  areas  separate  tlie  maxillae  from  the  postgenae  near  the 
ventral  margin  of  the  head.  This  unique  modification  of  the  maxillae 
agrees  with  the  striking  modifications  in  the  other  mouth-parts. 

The  figures  show  the  variations  in  other  genera  belonging  to  this 
group.  In  general  it  can  be  said  that  the  stipites  have  been  modified 
by  reduction  and  by  removal  to  the  ventral  margin  of  the  head  and  in 
some  cases  are  even  located  on  the  basiproboscis. 

The  maxillary  palpi  (mx.  pi)  of  the  Nematocera  figured  have  from 
two  segments — Geranomyia  (Fig.  382)  and  the  female  of  Psorophora 
(Pig.  266) — to  five  segments.  The  usual  number  is  four  or  five.  In 
the  Brachyeera  only  one  articulating  segment  is  present.  This  segment 
in  Tabanus  (Fig.  259)  connects  with  an  elongated  portion  of  the  stipes 
which  is  called  the  palpifer  by  some.  In  this  study  the  palpifer  is 
considered  as  wanting,  since  no  palpus  of  the  Diptera  possesses  over 


209]  HEAD    OF  DIPTERA  — PETERSON  39 

five  segments  and  furthermore  no  piece  is  present  at  the  base  of  any 
generalized  palpus  which  can  be  homologized  with  the  palpifer  of  gen- 
eralized iusects.  The  greatest  reduction  in  the  palpus  of  the  Nematocera 
occurs  in  Geranomyia  (Fig.  382),  while  in  the  Bi'achj-cera  the  palpus 
of  Mydas  (Fig.  271)  is  a  mere  lobe. 

A  small  finger-like  structure  arises  from  the  ventro-mesal  margin 
of  each  stipes  and  pi-ojects  mesad  to  the  caudal  aspect  of  the  hypo- 
pharynx  in  Tabanus  (Fig.  259)  and  Simulium  (Fig.  258).  These  pieces 
are  apparently  homologous  with  the  laciniae  (la)  of  generalized  insects. 
The  distal  ends  of  these  projections  articulate  against  the  caudal  aspect 
of  the  hypopharjTix  (Fig.  496  and  497),  and  in  this  respect  they  differ 
from  the  laciniae  of  generalized  insects.  These  pieces  in  Tabanus  have 
been  described  as  laciniae  by  Patton  and  Cragg  (1913). 

A  distinct  lobe  is  present  mesad  of  the  palpus  in  the  majority  of 
the  Diptera  that  do  not  have  a  ptilinum.  This  structure  is  unquestion- 
ably the  galea  (g),  for  in  specialized  insects  which  possess  a  distinct 
galea  the  lacinia  is  generally  reduced  in  size  and  in  some  cases  wanting. 
This  tendency  of  development  prevails  in  the  Diptera.  If  the  above 
pieces  in  Tabanus  and  Simulium  which  are  described  as  laciniae  are 
truly  such,  there  can  be  no  question  regarding  this  interpretation  of 
the  lobe  adjacent  to  the  palpus.  The  galeae  vary  considerably  in  size 
and  shape.  They  are  long  and  needle-like  in  Tabanus  (Fig.  259),  in 
the  female  of  Psorophora  (Fig.  266),  and  in  Empis  (Fig.  274),  Exo- 
prosopa  (Fig.  285),  and  Eulonchus  (Fig.  284a);  while  in  Trichocera 
(Fig.  260),  Disa  (Fig.  262),  Sciara  (Fig.  267),  Bittacomorpha,  Chi- 
ronomus  (Fig.  270),  Lonchoptera  (Fig.  280),  Sceuopinus  (Fig.  282), 
and  the  male  of  Psorophora  (Fig.  266)  they  are  greatly  reduced.  In 
Bibio  (Fig.  264)  and  Geranomyia  (Fig.  382)  they  are  mere  rudiments. 
They  are  wanting  in  Ehabdophaga  (Fig.  268),  Tipula  (Fig.  277), 
Helobia  (Fig.  385),  Aphioehaeta  (Fig.  278),  Pipunculus  (Fig.  279), 
Platypeza  (Fig.  272),  and  Dolichopus  (Fig.  284). 

The  development  of  the  maxillae  of  the  genera  possessing  a  ptilinum 
will  now  be  considered.  No  cardines  or  laciniae  are  present  in  this 
group.  The  maxillary  palpi  are  one-segmented  and  are  present  in  aU 
forms  except  Conops  (Fig.  305).  The  palpi  interpreted  here  as  maxil- 
lary palpi  have  been  called  labial  palpi  by  some  (e.g.,  "VVesche,  1909). 
The  stipites  and  galeae  are  present  in  aU  the  species  studied,  and  they 
undergo  decided  morphological  changes.  All  connection  or  association 
between  the  maxillae  and  the  invaginations  of  the  posterior  arms  of  the 
tentorium  has  been  lost.  This  loss  is  even  more  pronounced  than  in 
the  Brachycera,  since  in  all  but  a  few  species  figured  the  maxillae  are 
far  removed  from  the  head  and  situated  near  the  distal  end  of  the 


40  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [210 

well-developed  basiproboscis.  This  migration  of  the  maxillae  in  the 
Cyelorrhapha  has  not  altered  their  generalized  position  between  the 
labrum-epipharyux  and  the  labium. 

The  stipites  of  genera  having  a  ptilinum  show  all  stages  of  in- 
growth from  a  turned-in  fi-ee  edge  or  end  (st-e),  to  forms  in  which  it 
is  entirely  entad  of  the  membrane  of  the  basiproboscis,  as  in  Musca. 
Eristalis  (Fig.  286),  Eulonclms  (Fig.  284a),  and  Exoprosopa  (Fig. 
285)  are  the  only  forms  without  a  ptilinum  wliich  show  an  ental  growth 
of  the  stipites.  These  genera  make  a  good  starting  point  for  explaining 
the  characteristic  development  found  in  the  Acalyptratae  and  the  Calyp- 
tratae.  The  following  scheme  of  lines  and  dots  has  been  adopted  on 
the  drawings  in  order  to  show  the  degree  of  ingrowth  of  the  stipes.  A 
continuous  solid  line  on  the  stipes  indicates  a  definite  ectal  boiindary 
which  connects  with  the  membrane  of  the  basiproboscis.  A  broken  line 
indicates  an  ental  edge  or  end  which  is  free  of  the  membrane  between 
it  and  the  observer.  The  membrane  is  represented  by  stippling.  For 
convenience  of  description  and  homology  the  following  division  of  the 
stipes  has  been  made :  st  represents  the  ectal  portion  of  the  stipes  and 
st-e  the  ental  portion ;  and  st  is  further  divided  into  st-1  and  st-2  as 
seen  in  Coelopa  (Fig.  288). 

In  Exoprosopa  (Fig.  285)  and  Bulonchus  (Fig.  284a)  the  proximal 
end  of  the  stipes  is  free  and  entad  of  the  membrane,  while  the  cephalic 
edge  and  the  dorsal  end  are  entad  in  Eristalis  (Fig.  286).  From  a  form 
similar  to  Eristalis  it  is  possible  to  develop  a  stipes  which  would  resem- 
ble that  of  Sepsis  (Fig.  287),  Coelopa  (Fig.  288),  and  Calobata  (Fig. 
296).  In  Sepsis  the  palpus  is  greatly  reduced,  but  it  connects  with  an 
ectal  portion  of  the  stipes  (st)  which  in  turn  gives  rise  to  the  free  ental 
portion  (st-e).  The  free  ental  part  extends  ventrad  and  is  continuous 
with  the  galea,  which  emerges  from  the  membrane  near  the  base  of  the 
labrum  as  a  free  appendage.  The  stipes  of  Coelopa  (Fig.  288),  Sapro- 
myza  (Fig.  289),  and  Sphyracephala  (Fig.  293)  is  similar  to  that  of 
Sepsis,  but  in  these  forms  the  palpus  arises  from  the  cephalic  margin 
of  the  basiproboscis.  The  palpus  is  connected  with  the  stipes  proper 
by  means  of  a  long  chitinized  strip  (st-1)  which  is  usually  covered  with 
setae.  This  ectal  poi'tion  of  the  stipes  (st-1)  is  present  in  all  but  a  few 
genera,  such  as  Chloropisca  (Fig.  306),  Heteroneura  (Fig.  298),  Chyro- 
mya  (Fig.  299),  Loxocera  (Pig.  300),  and  Euaresta  (Fig.  292).  In 
a  number  of  forms,  particularly  in  the  Calypti-atae,  a  small  chitinized 
area  is  present  ventrad  of  the  palpus.  This  is  regarded  as  a  secondary 
chitinization.  The  ectal  portion  of  the  stipes  (st-2)  is  present  in  a 
majority  of  the  Acalyptratae  and  in  one  or  two  of  the  Calyptratae. 

The  ental  portion  of  tlie  stipes  (st-e)  is  always  present  in  the 
members  of  this  groiip.    In  Desmometopa  (Fig.  303),  Chloropisca  (Fig.. 


211]  HEAD    OF  DIPTERA—PETERSOX  41 

306),  Conops  (Fig.  305),  and  the  Calyptratae  it  has  no  connection  with 
the  ectal  portion  of  the  stipes  (st-2)  or  the  membrane,  and  by  many 
writers  is  commonly  called  the  apodeme.  The  free  so-called  apodeme 
is  unquestionably  derived  from  the  ental  ingrowth  of  the  stipes,  as 
illustrated  by  the  modifications  found  in  the  following  genera :  Coelopa 
(Fig.  2S8),'Sapromyza  (Fig.  289),  Tetanocera  (Fig.  297),  Archytas 
(Fig.  309),  Musea  (Fig.  304),  and  others. 

The  development  of  the  galea  (g)  maj'  be  traced  thruout  the  Cy- 
clorrhapha  in  a  manner  similar  to  that  of  the  stipes.  In  Eristalis 
(Fig.  286)  the  galea  is  a  long  free  appendage  arising  from  the  ventral 
end  of  the  stipes  near  the  proximal  end  of  the  labrum-epipharynx.  Its 
length  and  size  are  greatl.v  reduced  in  Sepsis  (Fig.  287),  but  its  position 
is  identical  with  that  of  Eristalis.  Thruout  the  majorit.v  of  the  Acalyp- 
tratae  the  position  of  the  galea  resembles  that  of  Sepsis.  Its  size  and 
form  undergo  some  change,  as  can  be  seen  in  the  figures.  In  the  Calyp- 
tratae and  some  of  the  Acalyptratae  the  galea  articulates  with  the 
proximal  end  of  the  labrum  and  is  more  or  less  firmly  connected  with 
the  same.  The  ectal  exposure  of  the  galea  is  very  small  in  these  forms. 
The  large  galea  of  the  Acalyptratae  has  been  considered  as  the  maxillary 
palpus  by  Wesche  (1902).    This  interpretation  is  highly  improbable. 

Lahiiim. — The  labium  is  the  most  specialized  and  characteristic 
appendage  of  the  mouth  of  Diptera.  Its  structural  modifications  are 
very  striking  among  the  specialized  genera,  such  as  the  Cyelorrhapha. 
These  modifications  are  largely  due  to  the  reduction  of  the  parts  and 
the  excessive  development  of  membranous  areas,  and  they  agree  with 
similar  types  of  modification  in  other  head-  and  mouth-parts. 

To  explain  the  imique  development  of  the  labium  of  Diptera,  it 
has  been  necessary  to  make  a  critical  study  of  the  generalized  condition 
of  this  appendage  as  it  occurs  in  the  Nematoeera  and  to  compare  it 
carefully  with  the  labia  of  more  generalized  insects.  As  is  well  known, 
the  labium  of  a  generalized  insect  is  the  posterior,  independent,  flap- 
like mouth-part,  made  iip  of  a  submeutum,  meutum,  and  ligula.  The 
ligula  is  further  divided  into  palpigers,  palpi,  paraglossae,  and  glossae. 
The  labium  of  a  generalized  dipteron  resembles  that  of  a  generalized 
insect  in  its  caudal  position  and  in  its  independent  condition,  but  it  is 
very  different  in  structure.  It  is  more  or  less  enlarged  and  not  flat 
and  flap-like,  and  the  palpi  and  palpigers  are  always  wanting,  so  far 
as  observed.  Since  the  position  of  the  palpi  and  the  palpigers  is  very 
useful  in  orienting  the  sclerites  of  the  labium  of  generalized  insects, 
their  absence  in  Diptera  makes  it  exceedingly  difficult  to  homologize  cor- 
rectly and  locate  the  submentum,  mentum,  and  the  parts  of  the  ligula. 
The  membranous  condition  of  the  labium  also  adds  to  this  difficulty. 


42  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [212 

In  order  to  get  some  light  on  this  problem,  a  study  was  made  of 
the  labium,  particularly  the  submeutum  and  mentum,  of  a  number  of 
generalized  insects  of  the  more  common  orders.  The  literature  of  this 
subject  was  examined,  but  no  satisfactory  results  were  obtained  from 
this  source.  After  a  careful  study  of  a  number  of  labia,  the  following 
general  characteristics  which  bear  upon  the  labium  of  Diptera,  were 
noted.  The  submentum  is  the  large  proximal  segment,  while  the  mentum 
is  usually  small  and  in  some  cases  very  thinly  chitinized  and  almost 
obsolete.  The  sutures  separating  the  mentum  from  the  submentum 
and  the  ligula  are  only  represented  by  small  remnants  in  Melanoplus. 
The  ligula,  so  far  as  observed,  comprises  the  movable  parts  of  the  labium, 
while  the  mentum  and  submentum  are  more  or  less  firmly  united  with 
the  head-capsule.  The  proximal  part  of  the  ligula  is  usually  well  de- 
veloped and  gives  rise  to  the  palpigers,  palpi,  paraglossae,  and  glossae. 
The  glossae  are  located  between  the  paraglossae,  and  in  a  number  of 
forms  a  distinct  depression  or  thickening  extends  proximad  between  the 
glossae  and  the  proximal  margin  of  the  ligula. 

With  these  observations  as  a  basis  for  comparison,  the  labium  of 
such  generalized  Diptera  as  Chironomus  (Fig.  371),  Simulium  (Fig. 
366),  Trichocera  (Fig.  365),  Dixa  (Fig.  375),  and  others  may  be  inter- 
preted as  follows.  The  mesal  membranous  area  of  the  caudal  aspect 
of  the  head,  which  is  bounded  by  the  postgenae  (po),  the  occipital 
foramen  (o.  f),  and  the  proximal  chitinized  piece  of  the  labium  (the), 
is  made  up  of  the  submentum,  mentum  (su. me),  and  the  cardines  (ca) 
and  stipites  (st)  of  the  maxillae  (mx).  Since  this  area  is  largely  mem- 
branous, it  is  impossible  to  determine  the  boundaries  of  these  sclerites. 
The  areas  laterad  of  the  cardines  and  the  stipites  apparently  belong  to 
the  maxillae,  while  the  area  mesad  of  these  parts  is  made  up  of  the 
submentum  and  mentum  (su.  me).  The  important  feature  concerning 
this  mesal  membranous  area  is  the  fact  that  the  maxillae  and  the 
labium  both  pla.y  a  part  in  its  formation.  This  undoubtedly  indicates 
that  the  submeutum  and  mentum,  of  a  more  or  less  fixed  nature  in 
generalized  insects,  have  been  more  extensively  fixed  in  the  Diptera, 
and  that  the  submentum  and  mentum  are  included  in  the  membrane 
developed  from  the  stipites  and  cardines.  Such  an  interpretation  is 
altogether  possible,  since  the  proximal  portions  of  the  maxillae  are  adja- 
cent to  the  submentum  and  mentum  in  generalized  insects. 

The  ligula  (Ig)  of  the  generalized  Diptera  agrees  with  the  ligula 
of  generalized  insects  in  that  it  is  the  movable  part  of  the  labium. 
Structurally  it  is  composed  of  a  well-developed  proximal  area  which 
gives  rise  to  two  large  bulb-like  paraglossae    (pgl)    and  to  two  small 


213]  HEAD    OF   DIPTERA— PETERSON  43 

membranous  glossae  (gl)  wliicli  are  located  between  the  paraglossae. 
The  palpigers  and  labial  palpi  are  wanting,  but  if  in  the  future  some 
form  is  discovered  wliieh  shows  these  structures,  thej'  will  undoubtedly 
be  found  on  the  area  liere  described  as  the  ligula.  The  proximal  portion 
of  the  ligula  has  a  decided  furrow  or  thickening  on  its  caudal  aspect 
along  the  meson.  This  thickening  is  characteristic  of  a  number  of 
Diptera  and  resembles  the  proximal  portion  of  the  ligula  of  a  number 
of  generalized  insects.  This  mesal  thickening  marks  the  line  of  fusion 
of  the  two  parts  of  the  labium  during  embryonic  development. 

The  above  interpretation  of  the  labium  is  on  the  whole  very  satis- 
factory for  the  numerous  modified  types  found  in  the  various  families 
of  the  Diptera,  and  with  this  interpretation  it  is  possible  to  formulate  a 
hj'pothetical  labium.  This  has  been  done  in  this  study;  but  there  have 
been  added  to  this  labium  the  early  stages  of  development  of  the  more 
important  secondary  structures  Mhich  are  characteristic  of  the  labia  of 
Diptera.  It  will  therefore  be  advisable  to  call  such  a  hypothetical  labium 
a  tj-pical  labium  in  order  to  distinguish  it  from  the  true  hypothetical 
type  of  other  parts  of  this  study. 

A  typical  labium  of  the  Diptera  (Fig.  1,  73,  140,  362,  and  363)  is 
made  up  of  a  submentum,  mentum,  and  ligula.  The  submentum 
and  mentum  (su.  me)  are  firmly  united  with  the  head  and  constitute 
the  greater  portion  of  the  mesal  membranous  area  of  the  caudal  aspect 
of  the  head.  The  ligula  (Ig)  is  the  large  swollen  and  movable  portion 
of  the  labium  and  consists  of  the  mediproboscis  (mpr)  and  the  disti- 
proboscis  (dpr).  The  mediproboscis  has  a  chitinized  area  on  its  caudal 
aspect  which  is  commonly  called  the  theca  (the).  The  distiproboscis  is 
composed  of  two  large  membranous  bulb-like  paraglossae  (pgl)  and  two 
small  membranous  glossae  (gl)  which  are  located  between  the  proximal 
parts  of  the  paraglossae.  The  important  and  characteristic  features  of 
a  typical  labium  are  the  chitinized  pieces  on  the  caudal  and  lateral  as- 
pects of  the  paraglossae  and  the  trachea-like  structures  on  the  mesal 
aspects.  The  details  of  the  various  parts  will  be  more  fully  discussed 
as  each  part  is  considered  and  its  modification  traced  thruout  the  order. 

The  submentum  and  mentum  (su.  me)  are  present  as  a  membranous 
area  in  a  majority  of  the  Nematocera  and  in  the  females  of  Tabanus 
(Fig.  74).  This  area  undergoes  considerable  modification,  as  was  seen 
iu  the  discussion  of  the  maxillae  and  postgenae,  and  is  illustrated  by 
the  figures.  Rhyphus  (Fig.  80  and  374)  is  apparently  the  only  genus 
which  has  within  this  area  a  chitinization  which  can  not  be  considered 
as  a  modification  of  the  maxillae  or  of  the  postgenae.  This  piece  is  a 
more  or  less  distinctly  chitinized,  inverted-flask-shaped  area  between 
the  maxillae.     If  this  is  a  primary  chitinization,  it  is  probably  a  rem- 


44  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [214 

nant  of  the  submentum.  A  similarly  situated  area  found  in  Mycetobia 
has  been  homologized  by  some  writers  with  that  of  Rhyphus.  This 
interpretation  is  undoubtedly  incorrect,  since  this  area  in  Mycetobia 
(Fig.  90)  gives  rise  to  chitinized  projections  at  its  ventro-lateral  angles 
and  these  in  turn  connect  with  the  maxillary  palpi  and  the  galeae. 
Furthermore,  the  relationship  which  this  piece  bears  to  the  proximal 
end  of  the  theca  (the)  would  tend  to  disprove  such  an  interpretation. 
This  piece  in  Mycetobia  is  undoubtedly  a  specialization  of  the  maxillae 
similar  to  the  modifications  found  in  Bibiocephala  (Fig.  83)  and  Rhab- 
dophaga  (Fig.  86).  In  all  genera  where  the  postgenae  have  grown 
together  on  the  meson  the  submentum  and  mentum  have  been  elimi- 
nated, unless  one  regards  the  area  between  the  ventral  margin  of  the 
head  and  the  theca  as  derived  from  these  areas.  This  area,  as  already 
described  for  the  Cyclorrhapha,  is  very  extensive  and  forms  the  caudal 
portion  of  the  basiproboscis  (bpr). 

The  proximal  portion  of  the  ligula  or  mediproboscis  (mpr)  of  the 
tj'pieal  labium  is  largely  membranous,  but  it  has  ou  its  caudal  aspect 
a  distinctly  chitinized  area,  the  theca  (the),  which  has  a  distinct  furrow 
on  its  meson.  The  shape,  size,  and  degree  of  chitinization  of  the  theca 
vary  greatly,  as  can  be  seen  in  Bibio  (Fig.  364),  Triehocera  (Fig. 
365),  RhjT)iius  (Fig.  374),  Promachus  (Fig.  376),  Tabanus  (Fig.  391), 
Chyromya  (Fig.  411),  Conops  (Fig.  420),  Rhamphomyia  (Fig.  424),  and 
Musca  (Fig.  466).  There  is  a  distinct  furrow  or  thickening  on  the 
meson  of  the  majority  of  the  Nematocera  and  the  Brachycera,  and  rem- 
nants of  these  thickenings  occur  also  among  the  Cyclorrhapha.  In  some 
of  the  Diptera  the  structural  condition  of  the  meson  has  a  marked  influ- 
ence on  the  shape  of  the  dorsal  and  ventral  margins  of  the  theca.  The 
cephalic  aspect  of  the  proximal  portion  of  the  ligula  of  a  typical  labium 
is  concave  and  membranous  and  connects  with  the  proximal  part  of  the 
lance-like  portion  of  the  hypopharynx.  In  the  Nematocera  the  cephalic 
aspect  resembles  the  typical  labium,  and  in  the  Brachycera  and  in  a 
majority  of  the  Cyclorrhapha  it  has  a  distinctly  chitinized  groove.  This 
is  well  "illustrated  by  Tabanus  (Fig.  392),  Eristalis  (Fig.  441),  and  a 
majority  of  the  Calyptratae.  The  degree  of  chitinization  varies  con- 
siderably, and  in  some  forms  heavy,  chitinized,  cord-like  pieces  extend 
along  the  sides  of  the  groove  from  the  glossae  to  the  proximal  end  of 
the  labium. 

The  distiproboscis  of  the  typical  labium  is  composed  of  two  large 
independent,  highly  membranous,  bulb-like  paraglossae  (pgl),  usually 
called  oral  lobes  or  labellae,  and  two  small  membranous  glossae  (gl). 
Each  paraglossa  has  on  its  lateral  and  caudal  aspects  a  Y-shaped  chi- 
tinized support  which  has  been  commonly  called  the  furca.     For  con- 


215]  HEAD    OF   DIPTERA  — PETERSON  45 

venienee  in  description  and  as  an  aid  in  tracing  the  development  of  the 
parts  of  the  furca  thruout  the  order,  it  has  been  divided  into  furca-1, 
which  is  the  stem  of  the  Y,  furca-2,  which  is  the  dorsal  arm  of  the  Y, 
and  furea-3,  which  is  the  ventral  arm.  The  furca  articulates  with  a 
small  sclerite  which  is  located  between  the  proximal  end  of  furca-1  and 
the  distal  end  of  the  chitinized  furrow  on  the  meson  of  the  theca.  This 
piece  has  been  called  the  sigma  (si).  Another  small,  independent 
sclerite  is  located  in  the  membrane  just  laterad  of  the  sigma  and  this 
may  be  kno'mi  as  kappa  (k).  Eacli  paraglossa  has  on  its  mesal  aspect 
two  trachea-like  structures  which  arise  from  the  proximal  portion  of 
the  glossa.    These  structures  are  commonly  called  pseud otracheae  (ps). 

A  general  survey  of  the  characteristics  of  the  paraglossae  of  the 
various  labia  shows  that  they  are  usually  bulb-like,  membranous,  and 
somewhat  flexible.  In  these  respects  they  diifer  decidedly  from  the 
firmly  chitinized,  flap-like  labia  of  many  generalized  insects.  Their  size 
and  shape  vary  greatly,  as  can  be  seen  in  Bibio  (Fig.  364),  Leia  (Fig. 
368),  Promachus  (Fig".  376),  Geranomyia  (Fig.  382),  Tipula  (Fig.  384), 
Tabanus  (Fig.  390),  Conops  (Fig.  417),  Empis  (Fig.  421),  Siphona 
(Fig.  458),  Musca  (Fig.  467),  Stomoxys  (Fig.  479),  and  Olfersia  (Fig. 
488).  The  use  to  which  the  labia  are  put  seems  to  have  some  influence 
on  their  form.  The  main  line  of  development  thruout  the  genera  figured 
is  toward  the  type  found  among  the  Calyptratae,  in  which  the  labia 
are  usually  large,  decidedly  membranous,  and  joined  together  on  the 
dorso-caudal  areas,  as  in  Hydrotaoa  (Fig.  475),  Sarcophaga  (Fig.  477), 
Sepsis  (Fig.  439),  Loxocera  (Fig.  461),  Tetanoeera  (Fig.  463),  and 
many  other  genera. 

The  membranous  development  of  the  paraglossae  is  not  always  a 
good  indication  of  the  main  line  of  specialization.  In  a  number  of 
scattered  genera,  Chironomus,  Rhjphus,  Aphiochaeta,  Chloropisca, 
Platypeza,  Leptis,  Psilocephala,  and  Lonchoptera,  it  is  next  to  impossi- 
ble to  make  out  the  chitinized  pieces,  such  as  kappa,  sigma,  and  furca, 
because  of  the  membranous  condition  of  the  entire  labium.  Outside  of 
the  above-named  forms,  the  chitinized  pieces  of  the  paraglossae  are 
usually  distinct  when  present.  These  supports  may  be  secondary  iu 
origin  or  they  may  be  remnants  of  former  chitinized  parts  of  the  para- 
glossae. It  is  possible  to  show  how  the  various  cliitinized  pieces  of  the 
majority  of  the  labia  may  have  been  developed  from  the  typical  form. 

The  sclerite  designated  as  kappa  (k)  on  the  typical  labium  is  onlj' 
present  in  Tabanus  (Fig.  390  and  391),  Tipula  (Fig.  388),  and  Bitta- 
comorpha  (Fig.  85).  No  otlier  dipteron  gives  any  evidence  whatever 
of  such  a  sclerite.  In  the  above-mentioned  genera  the  pieces  are  em- 
bedded in  the  membrane  laterad  of  the  ventral  ends  of  the  theca.    Some 


46  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [216 

one  has  interpreted  these  pieces  as  rudimentary  palpigers  or  palpi.  This 
may  or  may  not  be  correct.  It  is  possible  for  palpi  to  be  in  such  a 
position ;  but  since  no  other  genera  have  similar  pieces,  and  since  they 
are  so  decidedly  dissimilar  to  the  labial  palpi  and  palpigers  of  general- 
ized insects,  they  are  here  regarded  as  secondary  sclerites. 

The  sclerite  designated  as  sigma  (si)  is  present  as  a  chitinized  thick- 
ening at  the  ventral  end  of  the  theca,  as  in  Eristalis  (Fig.  443),  or  as 
a  distinct  piece,  as  in  a  majority  of  the  Brachycera  and  the  Cyclorrha- 
plia.  In  aU  genera  it  is  situated  between  the  ventral  margin  of  the 
theca  and  the  furca.  Only  a  few  genera  of  the  Nematocera,  such  as 
Tipula  (Fig.  388)  and  Psorophora  (Fig.  380),  have  these  sclerites.  They 
undergo  some  modification  in  size  and  structure  as  can  be  seen  in  the 
following  genera:  Tabanus  (Fig.  391),  Mydas  (Fig.  397),  Conops  (Fig. 
418),  Borborus  (Pig.  437),  Eristalis  (Fig.  443),  Coelopa  (Fig.  448), 
and  Scatophaga  (Fig.  470). 

The  furca  of  Bibio  (Fig.  315)  and  that  of  Tabanus  (Fig.  317) 
closely  resemble  the  typical  form.  In  Bibio,  furca-1  (f-1)  and  furca-2 
(f-2)  are  one  continuous  piece,  while  furca-3  (f-3)  is  a  distinct  arm. 
In  Tabanus,  furca-2  and  furca-3  are  distinctly  chitinized  areas  arising 
from  the  distal  end  of  furca-1.  Only  one  chitinized  support  is  present 
in  Sciara  (Fig.  314),  Rhabdophaga  (Pig.  313),  Psychoda  (Fig.  318), 
Stratiomyia  (Fig.  331),  and  Trichocera  (Fig.  311).  In  Trichocera  this 
support  has  a  decided  dorsal  bend  near  the  constriction  of  the  para- 
glossae.  This  bend  is  also  present  in  Psychoda  and  Stratiom^'ia,  but 
the  constriction  is  wanting.  The  distal  portion  of  the  furca  beyond  the 
bend  is  homologous  with  furca-2,  and  furca-3  is  wanting  in  these  forms. 
Furca-2  is  present  and  furca-3  is  wanting  in  Scenopinus  (Pig.  325)  ; 
furca-3,  however,  is  present  in  more  species  than  furca-2.  Such  is  the 
case  with  Borborus  (Fig.  342),  Chrysomyza  (Pig.  341),  Coelopa  (Pig. 
337),  Tetanocera  (Fig.  344),  Scatophaga  (Pig.  357),  Musca  (Pig.  351), 
and  Thelaira  (Pig.  346). 

Furca-1  (f-1)  varies  considerably  thruout  the  order.  In  general- 
ized forms  where  the  dorso-caudal  portions  of  the  paraglossae  are  not 
joined  together  the  fureae  are  always  well  separated.  They  are  also 
separated  in  some  forms  where  the  paraglossae  are  joined,  as  in  Mydas 
(Fig.  397)  and  Eristalis  (Pig.  443).  In  Chyromya  (Fig.  411),  Dro- 
sophila  (Pig.  454),  Tetanocera  (Fig.  463),  and  Sepsis  (Fig.  439),  an 
intermediate  piece  joins  the  mesal  ends  of  furcae-1  while  in  Sarcophaga 
(Pig.  477),  Musca  (Pig.  466),  Coelopa  (Pig.  448),  Sapromyza  (Pig. 
409),  Chrysomyza  (Pig.  457),  Heteroneura  (Pig.  459),  and  Oecothea 
(Pig.  452)  furcae-1  are  united  and  form  one  continuous  U-shaped  piece. 
This  type  of  fureae  is  present  among  the  Calyptratae.     The  fureae  of 


217]  HEAD    OF  DIPTERA  — PETERSON  47 

specialized  forms,  such  as  Olfersia  (Fig.  488),  Couops  (Pig.  418), 
Siphona  (Fig.  355),  Empis  (Fig.  421),  and  others,  are  not  differen- 
tiated, since  the  greater  part  of  the  lateral  aspects  of  the  paraglossae  is 
chitinized. 

In  the  typical  labium  two  simple  tracliea-like  structures,  commonly 
known  as  pseudotracheae  (ps),  arise  from  the  proximal  part  of  each 
glossa  and  extend  onto  the  mesal  membranous  aspect  of  each  paraglossa. 
These  trachea-like  structures  are  in  reality  small  chitinized  troughs 
which  serve  as  conduits  for  the  liquid  food.  Pseudotracheae  are  unique 
structures  and  peculiar  to  Diptera,  so  far  as  known.  They  are  present 
in  only  a  few  generalized  forms,  but  from  these  genera  it  is  possible 
to  develop  the  pseudotracheal  arrangement  and  structure  of  the  more 
specialized  Diptera.  It  is  consequently  as.sumed  that  the  pseudotracheae 
have  probably  arisen  only  once  within  the  order,  and  that  this  happened 
some  time  after  the  group  as  a  whole  -was  set  off  as  a  distinct  order. 

The  psedotracheae  (ps)  of  Tipula  (Fig.  383)  resemble  those  of  the 
typical  labium  in  that  the  two  main  pseudotracheae  arise  from  each 
glossa  and  extend  over  the  mesal  membranous  area  of  the  paraglossa, 
one  of  the  pseudotracheae  extending  caudad  and  the  other  cephalad. 
These  ducts  are  secondarily  branched  and  resemble  a  fern.  The  pseudo- 
tracheae of  Mycetophila  (Fig.  11)  and  Leia  (Fig.  368)  are  reduced  and 
only  the  caudal  pseudotracheae  extend  over  the  paraglossae.  The  para- 
glossae in  these  genera  are  united  along  the  meson  and  form  a  single 
large  lobe.  The  cephalic  pseudotracheae  are  indicated  by  small  rudiments 
in  Mycetophila  (Fig.  11).  The  pseudotracheae  in  these  forms  resemble 
the  typical  labium  in  that  they  are  simple,  unbranched,  chitinized 
troughs.  From  the  typical  labium,  or  from  the  p.seudotracheae  as  they 
occur  in  Tipula,  it  is  possible  to  derive  the  arrangement  and  structure 
of  the  pseudotracheae  as  they  are  found  in  Tabauus  (Fig.  390)  and 
similar  forms,  where  two  long  pseudotraclieal  trunks  (m.  ps)  extend 
cephalad  and  caudad  from  the  .glossae  (gl)  and  give  rise  to  many 
branches  on  their  ventral  side.  These  branches  extend  ventrad  over 
the  entire  mesal  area  of  the  paraglossa  (pgl).  The  arrangement  of  the 
pseudotracheae  of  most  Diptera  is  readily  derived  from  a  form  similar 
to  Tabanus.  The  arrangement  in  Scenopinus  (Pig.  400),  Psilocephala 
(Fig.  403),  and  many  of  the  Calyptratae  resembles  that  in  Tabanus. 
In  such  genera  as  Stratiomyia  (Fig.  396),  Oecothea  (Fig.  453),  Coelopa 
(Fig.  449),  and  Heteroneura  (Pig.  460)  no  main  collecting  duets 
(m.  ps)  extend  beyond  the  glossae.  In  many  genera,  such  as  Chloro- 
pisca  (Fig.  431)  and  Chyromya  (Fig.  412),  no  line  of  demarkation 
can  be  drawn  between  the  proximal  ends  of  the  pseudotracheae  and  the 
glossae. 


48  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [218 

U-shaped  or  open  ring-like  thickenings  are  present  in  the  pseudo- 
tracheae  of  the  more  specialized  Diptera.  They  do  not  occur  in  the 
simple  pseudotracheae  of  Mycetophila  or  in  some  of  the  highly  special- 
ized forms.  The  histological  structure  of  a  pseudotrachea  has  been 
clearly  demonstrated  by  several  workers.  According  to  Dimmock,  "The 
pseudotracheae  on  the  inner  surfaces  of  the  labellae  of  Musca  are  cylin- 
drical channels,  sunk  more  or  less  deeply  iuto  the  surfaces  of  the  labeUae 
according  to  the  amount  that  that  surface  is  inflated,  and  they  open  on 
the  surface  in  zig-zag  slits.  These  channels  are  held  open  by  partial 
rings,  more  strongly  chitinized  than  the  rest  of  the  membrane  of  the 
cylinder.  As  seen  from  above  in  Musca,  [Fig.  485],  the  pseudotracheae 
appear  to  be  supported  by  partial  rings,  one  end  of  each  of  which  is 

forked The  pseudotracheae  of  Eristalis  are  so    nearly    like 

those  of  Musca  [Calliphora]  vomitoria  that  I  have  not  figured  those 
of  the  former."  All  my  observations  of  the  histological  structure  of 
pseudotracheae  agree  with  those  made  by  Dimmock.  Tho  no  attempt 
was  made  to  work  out  the  detail  of  the  liistological  structure  in  the 
various  genera  studied,  a  number  of  interesting  facts  were  observed. 
The  chitinized,  taenidia-like  thickenings  (ps.  th)  in  Ochthera  (Fig.  445 
and  483)  are  large  U-shaped  structures  which  are  partially  embedded 
in  the  membrane.  The  ends  of  these  thickenings  project  considerably 
beyond  the  surface  of  the  membrane  and  resemble  these  structures  in 
Bombylius  major  (Fig.  482),  as  figured  by  Dimmock.  The  pseudo- 
Ira  cheae  of  Calobata  (Fig.  446)  have  developed  into  rows  of  small  chi- 
tinized teeth  (tee). 

The  pseudotracheal  area  of  the  paraglossae  undergoes  its  greatest 
specialization  in  forms  in  which  the  paraglossae  assume  a  biting  func- 
tion. This  biting  type  is  brought  about  by  the  development  of  distinct 
chitinized  teeth  arising  between  the  proximal  ends  of  the  pseudotracheae. 
Rudimentary  or  well-developed  teeth  occur  in  Musca  (Fig.  467),  Sar- 
cophaga  (Pig.  478),  Seatophaga  (Fig.  472),  Lispa  (Fig.  481),  and 
Stomoxys  (Fig.  480).  In  Musca  the  small,  chitinized,  so-called  pre- 
stomal  teeth  (tee)  are  present  between  the  proximal  ends  of  the  pseudo- 
tracheae. In  Seatophaga  and  Lispa  these  teeth  are  large  and  distinct. 
Their  greatest  development  occurs  in  Stomoxys,  and  so  far  as  observed 
pseudotracheae  are  wanting  in  this  form.  An  extensive  discussion  of 
the  development  and  the  structure  of  the  chitinized  teeth  of  the  para- 
glossae has  been  given  by  Patton  and  Cragg  (1913). 

The  glossae  (gl)  of  a  typical  labium  (Fig.  1  and  73)  are  two  small 
lobes  located  between  the  proximal  portions  of  the  paraglossae  distad 
of  the  furrow  on  the  theca  and  at  the  distal  end  of  the  cephalic  groove. 
Thruout  the  order  the  glossae  are  between  the  paraglossae  and  at  the 


219]  HEAD    OF  DIPTERA— PETERSON  49 

distal  end  of  the  cephalic  groove.  They  are  not  well-defined  structures 
in  all  labia.  In  ChLfonomus  (Fig.  371),  they  are  two  small  membranous 
lobes,  while  in  Simulium  (Fig.  366),  Rhabdophaga  (Fig.  367),  Bibio 
(Fig.  364),  and  Rhyphus  (Fig.  374)  they  have  the  form  of  a  single 
median  membranous  lobe.  The  glossae  of  Simulium  are  of  particular 
interest  since  they  have  a  great  number  of  minute  chitinized  thickenings 
which  radiate  from  the  proximal  end.  So  far  as  known  these  thicken- 
ings bear  no  relation  to  the  psedotracheae  of  the  paraglossae.  The 
glossae  of  Tabanus  (Fig.  391)  are  united  and  form  a  chitinized  triden- 
tate  piece  with  the  median  tooth  the  longest.  The  glossae  of  Lonchop- 
tera  (Fig.  407)  illustrate  a  form  intermediate  between  a  median  spine, 
such  as  occurs  in  Psorophora  (Fig.  381),  Aphiochaeta  (Fig.  393),  Empis 
(Fig.  422),  and  Exoprosopa  (Fig.  426),  and  the  U-shaped  structure 
characteristic  of  the  Cyclorrhapha.  The  glossae  of  the  Calyptratae  re- 
semble in  general  the  glossae  of  Musea  (Fig.  465).  In  the  genera  of 
this  group  the  cephalic  ends  of  the  U-shaped  piece  are  free  and  project 
cephalad  from  the  point  of  attachment  of  the  pseudotracheae.  The 
glossae  are  not  well  defined  in  a  few  genera,  Sapromyza  (Fig.  410), 
Chyromya  (Fig.  412),  and  Chloropisca  (Fig.  431),  for  example,  and 
it  is  impossible  to  differentiate  the  glossae  from  the  chitinized  groove 
of  the  mediproboscis  and  the  proximal  ends  of  the  pseudotracheae.  The 
glossae  of  Promachus  (Fig.  379)  are  specialized  in  that  they  give  rise 
to  two  thickenings  which  extend  dorsad  in  the  groove  of  the  labium 
and  serve  as  guides  for  the  hypopharynx  and  galeae. 

EPIPHARYNX   AND    HYPOPHARYNX 

The  anterior  end  of  the  alimentary  canal  of  the  Orthoptera  and 
of  insects  in  general  is  divided  transversely  into  two  parts,  one  forming 
the  cuticular  lining  of  the  clypeus  and  labrum  and  the  other  the  lining 
of  the  opposite  side  of  the  mouth  ca^^ty.  The  portion  lining  the  clypeus 
and  labrum  is  known  as  the  epipharynx  (ep),  and  that  of  the  opposite 
side  as  the  hypopharynx  (hp).  Each  lining  may  be  subdivided  into 
several  parts.  These  are  of  particular  significance  in  a  study  of  the 
epipharj'nx,  which  has  a  distinct  chitinized  mesal  piece,  and  two  lateral 
chitinized  pieces  which  are  situated  near  the  clypeo-labral  suture.  These 
lateral  pieces,  which  have  been  designated  as  tormae  (to),  and,  so  far 
as  I  know,  are  described  here  for  the  first  time,  project  cephalad  toward 
the  clypeo-labral  suture  in  Melanoplus  (Fig.  515)  and  Gryllus  (Fig. 
516)  and  connect  with  both  the  labrum  and  clypeus.  In  Gryllus  they 
are  interpolated  between  the  clypeus  and  the  labrum  and  appear  as 
small  triangular  sclerites  on  the  cephalic  aspect.  The  tormae  of  Peri- 
planeta  (Fig.  514)   are  not  as  well  developed  as  in  the  above-named 


50  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [220 

genera,  but  they  are  present  and  project  toward  the  cephalo-lateral 
corners  of  the  labruni.  The  caudal  end  of  the  epipharynx  in  many  in- 
sects gives  rise  to  long  chitinized  arms  which  have  been  called  cornua 
(eu).  The  hypopharynx  may  be  subdivided  into  a  distal,  unpaired,  me- 
dian piece,  which  is  usually  called  the  hypopharynx,  and  a  proximal 
paired  area. 

The  chitinized  portion  of  the  anterior  end  of  the  alimentary  canal 
of  Diptera  can  be  homologized  with  the  epipharynx  and  the  hypophar- 
ynx of  generalized  insects.  The  following  hypothetical  epipharynx 
and  hypopharynx  (Fig.  493)  and  their  closely  associated  parts  have 
been  constructed  for  Diptera.  In  the  figures  of  tlie  lateral  views  of  the 
hypothetical  type  an  enlarged,  three-sided,  chitinized  tube  extends  cau- 
dad  from  the  dorsal  end  of  the  hypopharynx  and  epipharynx.  It  has 
been  called  the  oesophageal  pump  (oe.  p).  This  is  not  a  part  of  the 
epipharynx  or  of  the  hypopharynx,  but  is  a  modification  of  the  pharynx, 
a  portion  of  the  alimentary  canal.  All  of  the  chitinized  parts  ventrad 
of  the  membranous  area  at  the  cephalic  end  of  the  oesophageal  pump 
belong  to  the  epipharynx  and  the  hypopharynx.  The  dorsal  ends  of 
the  epipharynx  and  the  hypopharynx  are  united  and  form  a  single  chi- 
tinized tube,  and  this  has  been  called  the  basipharynx  (bph).  Except 
for  this  union,  the  epipharynx  and  the  hypopharynx  are  continuous 
chitinized  pieces  with  lance-like  distal  ends.  The  distal  portion  of  the 
epipharynx  is  joined  to  the  labrum  by  a  membrane  along  its  lateral 
margin.  The  tormae  in  the  hypothetical  type  project  from  the  lateral 
margins  of  the  epipharynx  and  unite  with  the  latero-ventral  portions 
of  the  fronto-clypeus  (fr.  c).  Two  projections  occur  at  the  dorsal  end 
of  the  basipharynx,  and  these  are  considered  homologous  with  the  cor- 
nua (cu)  of  the  epipharynx  of  generalized  insects.  The  distal  end  of 
the  hypopharynx  is  a  free  lance-like  organ,  and  a  salivary  duct  (s.  d) 
enters  its  proximal  end  just  dorsad  of  the  place  where  it  joins  the 
labium  (li).  The  salivary  duct  extends  thru  the  hypopharynx  to  its 
distal  end. 

The  oesophageal  pump  of  the  alimentary  canal  is  closely  associated 
with  the  epipharynx  and  hypopharynx  in  all  the  Nematocera  and  in 
Promachus  (Fig."  517),  Tabanus  (Fig.  494),  Leptis  (Fig.  520),  and 
Psiloeephala  (Fig.  533)  of  the  Brachyeera.  In  a  majority  of  the  above 
forms,  the  oesophageal  piimp  is  an  elastic,  semi-chitinized,  three-sided 
tube  with  muscles  connecting  with  each  of  its  surfaces.  A  contraction 
of  these  muscles  expands  the  tube,  which  \ipon  their  relaxation  assumes 
its  normal  shape.  In  some  forms,  as  Tabanus  and  Promachus,  there 
is  only  one  chitinized  elastic  surface.  In  a  number  of  genera,  as  Chi- 
ronomus  (Fig.  531),  Psychoda  (Fig.  529),  and  Leptis  (Fig.  520),  the 


221]  HEAD    OF  DIPTERA— PETERSON  51 

tube  is  more  or  less  membranous  and  not  distinctly  three-sided.  Tlie 
oesophageal  pump  is  wanting  in  all  the  Diptera  except  those  named, 
and  the  membranous  oesophagus  connects  directly  with  the  basipharynx. 
The  oesophageal  pump  shows  considerable  variation  in  its  shape,  posi- 
tion, and  size,  as  can  be  seen  in  the  figures  of  Bibio  (Fig.  523),  Rhyphus 
(Pig.  508)  and  others. 

The  basipharynx  (bph)  is  interpreted  as  including  all  of  the  united 
portions  of  the  epipharynx  and  the  hypopharynx,  but  the  extent  of 
this  union  varies  somewhat  in  the  different  genera.  In  a  majority  of 
the  Nematocera  no  sutures  or  constrictions  occur  between  the  basiphar- 
ynx and  the  lance-like  portions  of  the  epipharynx  and  the  hypophar- 
ynx. Such  constrictions  and  secondary  sutures  do  occur  in  a  majority 
of  the  Brachycera,  as  in  Leptis  (Fig.  520)  and  Promaehus  (Fig.  517), 
and  in  all  of  the  Cyclorrhapha.  The  basipharynx  (bph)  varies  in  size 
and  shape,  as  can  be  seen  in  the  figures.  Muscles  connect  with  the 
cephalic  and  caudal  aspects  of  the  basipharynx,  those  on  the  cephalic 
aspect  expanding  the  basipharynx  and  thus  producing  suction.  This 
sucking  apparatus  is  well  developed  in  all  forms  which  have  no  oesophag- 
eal pump.  The  chitinized  projections  at  the  dorsal  end  of  the  basiphar- 
ynx, called  the  cornua  (cu),  vary  in  shape  and  size.  Some  are  blunt, 
others  long  and  narrow,  as  in  Leptis  and  the  Calj^ptratae,  and  still 
others  are  disk-shaped,  as  in  Promaehus  (Fig.  517). 

Distinct  tormae  (to)  are  present  in  Diptera  except  in  a  few  species 
of  the  Nematocera.  In  all  the  Nematocera  and  in  Leptis  (Fig.  520), 
Psilocephala  (Pig.  533),  Platypeza  (Pig.  543),  Aphiochaeta  (Fig.  544), 
Lonchoptera  (Fig.  539),  and  Scenopinus  (Fig.  538),  they  resemble  the 
hypothetical  type  in  that  they  join  with  the  fronto-clypeus.  In  other 
genera  the  tormae  have  an  exposed  portion  located  ventrad  of  the 
fronto-clypeus  and  all  connection  between  the  fronto-clypeus  and  the 
tormae  is  lost,  except  in  Simulium  (Fig.  497)  and  Tabanus.  The 
variations  in  the  shape  and  the  extent  of  the  tormae  is  well  illustrated 
by  the  numerous  figures.  The  so-called  fulcrum  described  by  numerous 
morphologists  for  the  Calyptratae  is  composed  of  the  tormae  and  the 
basipharynx.  A  more  or  h^ss  distinct  secondary  sutiire  (s.  s)  is  shown 
in  tlie  drawings  as  separating  the  tormae  from  the  basipharynx,  and 
the  broken  line  on  the  tormae  indicates  the  place  of  connection  of  the 
membrane  of  the  basiproboscis  with  the  tormae.  In  figures  of  the 
Nematocei'a  and  of  forms  in  which  the  tormae  connect  with  the  fronto- 
clypeus  the  broken  line  indicates  the  place  of  union  between  these  parts. 

The  epipharynx  (ep)  is  present  and  closely  associated  with  the 
labrum  in  all  Diptera  having  functional  mouth-parts.  The  interrela- 
tionship  between   the  epipharj'nx  and  the  labrum  has  been  discussed 


52  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [222 

under  the  heading  labrum.  The  epipharynx  in  a  number  of  generalized 
Diptera,  such  as  Tabanus  (Pig.  494),  Simulium  (Fig.  497),  Dixa  (Fig. 
501),  Limnobia  (Fig.  507),  and  Sciara  (Fig.  513),  resembles  the  hypo- 
thetical type.  In  the  majority  of  the  Diptera  it  differs  from  the  hypo- 
thetical type  in  that  it  is  completely  separated  from  the  basipharynx 
by  a  constriction  or  a  secondary  suture.  This  hinge  in  the  epij^harynx 
permits  the  proboscis  to  bend  at  this  point  when  it  is  withdrawn  into 
the  oral  cavitj\  The  lance-like  portion  of  the  epipharynx  in  the  Calyp- 
tratae  and  some  other  forms  is  completely  separated  from  the  basiphar- 
ynx by  the  development  of  a  special  piece  which  is  commonly  called 
the  hyoid  (hy).  The  lance-like  portion  of  the  hypopharynx  also  articu- 
lates against  the  hyoid.  The  hyoid  is  a  secondary  sclerite  which  origi- 
nated from  the  epipharynx  or  the  hypopharynx  and  serves  the  purpose 
of  keeping  open  the  alimentary  canal,  which  passes  thru  it.  A  structure 
similar  to  the  hyoid  of  Musca  (Fig.  600)  is  found  in  Stomoxys  (Fig. 
599),  where  a  large  and  strong  trachea-like  tube  extends  between  the 
dorsal  ends  of  the  lance-like  portions  of  the  epipharynx,  the  hypophar- 
ynx, and  the  basipharynx. 

In  size  and  shape  the  epipharynx  agrees  more  or  less  closely  with 
the  labrum.  The  epipharynx  in  sucking  Diptera  is,  as  a  rule,  long  and 
needle-like,  while  in  other  forms  it  is  usually  short  and  blunt.  In  many 
genera  of  the  Acalyptratae  it  has  a  secondary  transverse  suture  near  its 
distal  end,  as  shown  in  Sepsis  (Fig.  583)  and  Eristalis  (Fig.  588). 

A  few  genera  show  special  modifications  of  the  epipharynx.  This 
is  particularly  true  of  Dolichopus  (Fig.  524  and  528).  In  this  genus 
the  epipharynx  closely  resembles  the  hypothetical  type  in  the  presence 
of  a  distinct  membrane  between  the  labrum  (1)  and  the  epipharynx 
(ep).  The  specialization  of  the  epipharynx  consists  in  the  bifurcation 
of  its  distal  end  and  in  the  presence  of  a  long  club-shaped  piece  which 
projects  from  its  meson  dorsad  into  the  cavity  formed  by  the  basiphar- 
ynx, the  tormae,  and  the  fronto-clypeus.  These  modifications  are 
peculiar  to  species  of  the  Dolichopodidae.  The  bifurcations  at  the  distal 
end  are  of  particular  interest,  since  they  have  been  interpreted  as  man- 
dibles by  Langhoffer  (1888).  They  are  much  longer  in  some  of  the 
genera  of  the  family  than  in  others.  The  lateral  and  caudal  views  of 
the  epipharynx  and  the  hypopharynx  of  Dolichopus  show  clearl.v  the 
relation  these  projections  have  to  the  other  parts,  and  justify  the  inter- 
pretation here  given. 

The  single,  median,  distal,  lance-like  portion  of  the  hypopharynx 
is  present  in  all  but  a  few  of  the  genera  studied.  The  cephalic  portion 
of  the  labium  usually  connects  with  the  lance-like  portion  of  the  hy- 
popharynx just  ventrad  of  the  point  of  entrance  of  the  salivary  duct. 


223]  HEAD    OF  DIPTERA— PETERSON  53 

In  a  few  cases,  as  in  Borborus  (Fig.  565  and  567),  the  liypopliaryux  is 
completely  fused  with  the  labium,  while  in  others,  as  in  Euaresta  (Fig. 
572),  it  is  nearly  so.  In  a  majority  of  the  genera  the  secondary  separa- 
tion of  the  lance-like  portion  of  the  hypopharynx  from  the  basipharynx 
corresponds  with  the  similar  separation  in  the  epipharjTix.  The  shape 
and  size  of  the  hj^jopharj-nx  also  vary  considerably,  as  can  be  seen  in 
the  figiires.  In  mouth-parts  titted  for  sucking  and  piercing,  the  hy- 
popharynx is  usually  long  and  needle-like ;  while  in  licking  forms  (most 
Calyptratae),  it  is  greatly  reduced. 

The  salivary  duct  (s.  d)  enters  the  proximal  portion  of  the  lance- 
like part  of  the  hypopharynx  and  in  most  cases  it  is  carried  as  a  duct 
or  groove  along  the  cephalic  surface  of  that  organ  to  the  distal  end. 
The  course  of  this  duct  or  groove  is  indicated  by  broken  lines  in  the 
figures  of  the  caudal  aspect  of  the  hypopharynx.  The  salivary  duet 
before  entering  the  hypopharjoix  is  enlarged  and  bulb-like  in  many 
species.  In  Tabanus  (Fig.  494)  the  salivary  bulb  (s.  b)  is  a  chitinized 
structure  continuous  with  the  hypopharynx,  while  in  Promachus  (Fig. 
517)  it  is  chitinized,  but  separated  from  the  hj-popharynx.  A  chitinized 
bulb  and  an  enlarged  membranous  swelling  are  both  present  in  Dolicho- 
pus  (Fig.  528). 

The  peculiar  epipharyux  and  hypopharynx  of  Olfersia  (Fig.  606) 
can  be  homologized  with  the  more  common  types  found  thruout  the 
order.  The  principal  difference  is  in  the  shape  and  position  of  the 
basipharj-nx,  the  tormae,  and  the  hyoid.  The  two  lance-like  structures 
embedded  in  the  deep  membranous  depression  about  the  oral  cavity 
are  the  labrum-epipharynx  and  the  lance-like  part  of  the  hypopharynx. 
The  long,  crescent-shaped  piece  which  extends  cephalad  from  the  proxi- 
mal end  of  the  labrum-epipharrax  to  the  pear-shaped  piece,  is  homolo- 
gous with  the  hyoid  (hy),  and  the  pear-shaped  piece  with  which  the 
hyoid  connects  is  composed  of  the  tormae  (to)  and  the  basipharynx 
(bpli).  The  exposed  parts  of  the  tormae  in  the  membrane  ventrad  of 
the  head  are  very  small  in  this  genus. 

Only  rudiments  of  mouth-parts  are  found  in  the  head  of  Gastrophi- 
lus  (Fig.  490  and  492).  The  anterior  end  of  the  alimentary  canal  is  a 
simple  chitinized  tube  which  leads  to  the  small  opening  on  the  ventral 
aspect  of  the  head.  This  tube  undoubtedly  originated  from  the  epiphar- 
ynx  and  the  hypopharynx.  The  mouth-parts  are  greatly  reduced  or 
wanting.  It  is  possible  that  the  small  bvdb-like  structures  located 
latero-caudad  of  the  opening  are  remnants  of  the  labium.  It  is  impos- 
sible to  homologize  the  other  minute  modifications  surrounding  the 
mouth-opening. 

In  the  Cyrtidae,  as  Oncodes  (Fig.  109,  486,  and  487),  the  mouth- 


54  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [224 

parts  show  a  greater  reduction  than  in  Gastrophilus,  while  in  species 
of  Bulonchus  (Fig.  364a)  they  are  well  developed.  In  Oncodes  a  chi- 
tiuized  ring  is  present  in  the  membrane  which  covers  the  oral  cavity, 
and  a  broad  plate  extends  dorsad  from  its  caudal  margin,  giving  rise 
to  a  small  membranous  tube,  the  oesophagus,  which  has  no  opening  to 
the  exterior  as  far  as  could  be  determined.  It  is  impossible  to  homolo- 
gize  the  parts  within  the  oral  cavity.  The  ental  plate  which  gives  rise 
to  the  oesophagus,  may  be  homologous  with  the  basal  portion  of  the 
epipharynx  and  the  hypopharynx. 

A  general  survey  of  the  epipharynx  and  hypopharynx  shows  that 
the  relationship  between  these  parts  and  the  head-capsule  corresponds 
with  the  relationship  between  the  mouth-parts  and  the  head.  Since  the 
epipharynx  and  the  hypopharynx  are  always  connected  with  the  labrum 
and  the  proximal  part  of  the  labium,  they  are  projected  ventrad  when 
the  labrum  and  labium  are  extruded.  The  interrelation  of  the  mouth- 
parts  and  the  epipharynx  and  hypopharynx  is  fixed,  never  changing  thru- 
out  the  order,  no  matter  what  specialization  may  take  place.  The  espe- 
cially striking  feature  of  the  epipharynx  and  the  hpopharynx  in  various 
genera  which  have  functional  mouth-parts,  is  the  decided  similarity  of 
the  two  thruout  the  order,  as  shown  by  the  various  figures.  The  parts 
undergo  secondary  changes  in  their  size  and  shape,  but  in  no  case  where 
the  mouth-parts  are  functional  is  there  an  entire  loss  of  a  part,  which, 
however,  happens  in  many  cases  with  the  mouth-appendages.  The  epi- 
pharynx and  hpopharynx  of  the  Calyptratae  in  particular  show  a  devel- 
opment of  joints,  secondary  sclerites,  and  membranous  areas,  which 
permit  a  considerable  amount  of  flexibility. 

SUMMAEY 

This  investigation  deals  with  the  homology  of  all  the  sclerites  of 
the  fixed  and  movable  parts  of  the  head  of  one  or  more  representatives 
of  fifty-three  of  the  fifty-nine  families  of  the  Diptera  of  North  America 
as  listed  by  Aldrich.  With  this  large  series  it  has  been  possible  to 
make  clear  a  number  of  little-understood  relationships  and  structural 
modifications  in  the  head  and  mouth-parts,  and  also  to  point  out  their 
homology  with  the  corresj^onding  parts  and  areas  in  insects  of  other 
orders.  The  six  hundred  and  more  figures  show  the  form  and  structure 
of  all  the  parts  for  each  of  the  families  studied. 

Modifications  of  the  fixed  and  movable  parts  usually  take  the  form 
of  reduction,  change  of  shape,  loss  of  chitinization,  or  expansion  of  the 
membranous  areas.  The  different  parts  have  been  discussed  separately, 
and  a  hypothetical  or  typical  form  has  been  constructed  for  each  part. 


225]  HEAD    OF  DIPTERA—PETERSON  55 

Oue  of  the  most  important  conclusions  concerning  the  generalized 
head-capsule  relates  to  the  position  of  the  epicranial  suture.  The  stem 
of  this  suture  along  the  dorso-meson  represents  the  line  of  fusion  of 
the  paired  sclerites  of  the  head,  while  the  arms  of  the  suture  ventrad 
of  the  antennal  fossae  enclose  the  unpaired  sclerites  of  the  head.  This 
suture  resembles  the  epicranial  suture  in  the  immature  stages  and  the 
adult  forms  of  all  the  generalized  members  of  the  more  common  orders. 

Two  unpaired  sclerites,  front  and  clypeus,  are  enclosed  by  the  fork 
of  the  epicranial  suture,  and  in  all  but  one  or  two  genera  form  a  con- 
tinuous area  called  the  fronto-clypeus. 

The  labrum  is  an  unpaired,  distinct,  tongue-like  structure  situated 
ventrad  of  the  fronto-clj-peus.  It  is  joined  to  the  epipharynx  and  the 
resulting  structure  is  kno^vn  as  the  labrum-epipharynx. 

The  tormae  are  chitinized  lateral  pieces  of  the  epipharynx  which 
project  cephalad  and  unite  with  the  fronto-clypeus  in  generalized  Dip- 
tera.  They  are  also  present  in  such  generalized  insects  as  the  Orthop- 
tera.  In  the  more  specialized  Diptera  the  tormae  are  interpolated  be- 
tween the  fronto-clypeus  and  the  labrum,  and  in  all  but  a  few  genera 
lose  all  connection  with  the  chitinized  portions  of  the  fronto-clypeus. 
Their  exposed  surface  is  best  seen  from  a  cephalic  view. 

The  crescent-shaped  frontal  suture  dorsad  of  the  antennal  fossae 
marks  the  line  of  invagination  of  the  ptUinum.  The  origin  of  the 
ptilinum  has  not  been  determined. 

The  vertex  is  the  paired  continuous  area  on  the  cephalic  aspect  of 
the  head,  and  the  region  of  the  vertex  ventrad  and  mesad  of  each  com- 
pound eye  is  a  gena. 

The  compound  eyes  are  usually  large  and  located  on  the  cephalo- 
lateral  aspects  of  the  head.  Thej'  show  secondary  sexual  characters  in 
a  greater  number  of  species  than  do  anj-  other  of  the  fixed  and  movable 
parts.  The  three  ocelli  are  arranged  in  the  form  of  a  triangle  aud 
located  on  the  vertex  dorsad  of  the  bifurcation  of  the  arms  of  the  epi- 
cranial suture. 

The  occiput  and  postgenae  are  continuous  areas  of  the  caudal  sur- 
face. The  former  occupies  the  dorsal  portion  and  is  secondarily  modified 
about  the  occipital  foramen  to  form  the  parocciput.  The  postgenae  are 
the  two  areas  of  the  ventral  half,  separated  by  a  membrane  in  gener- 
alized forms  and  united  ventrad  of  the  occipital  foramen  in  all  the 
Brachycera  and  the  Cyclorrhapha.  They  are  also  secondarily  di'vided 
into  parapostgenae  along  the  mesal  membrane. 

The  tentorium  of  generalized  Diptera  is  represented  by  the  usual 
three  pairs  of  arms  and  a  rudimentary  body.  It  undergoes  striking 
modifications,  aud  influences  to  a  considerable  extent  the  detailed  struc- 


56  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [226 

ture  of  the  head.  The  relation  between  the  invaginations  of  the  ten- 
torium and  the  movable  appendages  of  the  mouth,  wliich  is  so  important 
a  feature  of  all  generalized  insects,  is  also  characteristic  of  the  members 
of  this  order. 

The  development  of  the  antennae  from  a  generalized  filiform  type 
to  that  found  among  the  Cyclorrhapha  can  be  traced  on  the  figures. 

Only  a  few  generalized  Diptera  have  mandibles.  These  are  only 
present  in  the  females  except  in  Simulium,  in  which  they  are  well 
developed  in  both  sexes. 

All  Diptera  having  functional  mouth-parts  have  maxillae.  The 
maxillae  of  generalized  Diptera  resemble  the  maxillae  of  generalized 
insects  except  for  the  absence  of  palpifers  and  the  fusion  of  the  cardines 
and  stipites  with  the  head-capsule.  The  maxillae  undergo  considerable 
modification,  and  are  reduced  to  a  mere  ental  rod  and  a  palpus  in  the 
Calyptratae. 

The  labium  is  the  most  characteristic  and  specialized  appendage  of 
the  mouth,  and  shows  modifications  due  to  reduction  and  membranous 
development.  The  palpigers  and  labial  palpi  are  always  wanting.  The 
submentum  and  mentum  are  represented  by  a  membranous  area  of  the 
caudal  surface  of  the  head.  The  ligula,  or  the  movable  portion  of  the 
labium,  has  a  basal  part  which  usually  gives  rise  to  two  large  bulb-like 
paraglossae  and  to  glossae  situated  between  them.  The  paraglossae  are 
specialized,  and  have  chitiuized  areas  on  their  lateral  and  caudal  sur- 
faces and  pseudotracheae  on  their  mesal  surface. 

The  parts  of  the  epipharynx  and  the  hypopharynx  can  be  homolo- 
gized  with  the  corresponding  parts  in  generalized  insects.  There  is  a 
great  similarity  in  the  form  of  the  epipharynx  and  hypopharynx  of  all 
Diptera,  which  is  especially  striking  when  considered  in  connection  with 
the  modifications  that  have  taken  place  in  all  other  parts. 

The  various  mouth-parts  show  striking  modifications  thruout  the 
order,  but  all,  including  the  epipharjrax  and  the  hypopharjmx,  retain 
their  relative  positions,  even  tho  they  may  be  extruded  from  the  head- 
capsule  for  a  considerable  distance,  as  in  some  of  the  Calyptratae.  The 
proboscis  of  the  Cyclorrhapha  is  composed  of  the  labium,  maxiUae, 
hypopharynx,  labrum-epipharynx,  and  tormae.  The  paraglossae  of  the 
labium  form  the  large  lobes,  or  labeUae,  at  its  distal  end. 

The  mouth-parts  of  Oncodes  and  Gastrophilus  are  not  functional, 
and  are  so  greatly  reduced  that  it  is  difficult  to  homologize  their  parts. 


227]  HEAD    OF  DIPTERA— PETERSON  57 


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231] 


HEAD    OF  DIPTERA— PETERSON 


61 


EXPLANATION  OF  PLATES 
ABBREVIATIONS   USED 


a.a 

Anterior  arms  of  the  tentorium 

i.a.d 

Invagination  of  the  anterior  and 

a.e.s 

Arms  of  the  epicranial  suture 

dorsal  arms  of  the  tentorium 

a.f 

Antennal  fossa 

i.d 

Invagination  of  the  dorsal  arm 

al.c 

Alimentary  canal 

of  the  tentorium 

ant 

Antenna 

i.p 

Invagination    of    the    posterior 

ar 

Arista 

arm  of  the  tentorium 

a.s 

Antennal  sclerite 

k 

Kappa  (sclerite) 

bph 

Basipharynx 

1 

Labrum 

bpr 

Basiproboscis 

la 

Lacinia 

b.t 

Body  of  the  tentorium 

le 

Labella 

c 

Clypeus 

l.ep 

Labrum  epipharynx 

ca 

Cardo 

Ig 

Ligula 

c.e 

Compound  eye 

li 

Labium 

ch 

Chitinized 

m 

Membrane 

ch.th 

Chitinized  thickening 

md 

Mandible 

c.l.s 

Clypeo-labral  suture 

me 

Mentum 

cu 

Cornu 

mpr 

Mediproboscis 

d.a 

Dorsal  arms  of  the  tentorium 

m.ps 

Main   pseudotracheae 

de 

Depression 

mx 

Maxilla 

dpr 

Distiproboscis 

nix.pl 

Maxillary  palpus 

ep 

Epipharynx 

n.s 

Neck  sclerite 

e.s 

Epicranial  suture 

oc 

Ocellus 

f 

Furca,  also  f-i,  f-2,  and  f-3 

oca 

Ocellar  area 

fa 

Facet 

occ 

Occiput 

fl 

Flagellum 

oe 

Oesophagus 

fr 

Front 

oe.p 

Oesophageal  pump 

fr.c 

Fronto-clypeus 

o.f 

Occipital  foramen 

fr.s 

Frontal  suture 

0.1 

Oral  lobe 

g 

Galea 

o.s 

Ocular  sclerite 

ge 

Gena 

p.a 

Posterior  arms  of  the  tentorium 

gl 

Glossa 

pd 

Pedicel 

h 

Hook 

pgl 

Paraglossa 

hp 

Hypopharynx 

po 

Postgena 

hy 

Hyoid 

pocc 

Parocciput 

i.a 

Invagination  of  the  anterior  arm 

ppo 

Parapostgena 

of  the  tentorium 

pr 

Proboscis 

62 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[232 


ps 

Pseudotrachea 

so 

Sense  organ 

ps.th 

Pseudotracheal  thickening 

s.s 

Secondary  suture 

Pt 

Ptilinum 

St 

Stipes,     st-i  and  st-2  ectal  part, 

r.d.a 

Rudimentary  dorsal  arms  of  the 

st-e  ental  part 

tentorium 

su 

Submentum 

r.p.a 

Rudimentary  posterior  arms   of 

su.me 

Submentum  and  mentum 

the  tentorium 

t 

Tentorium 

s 

Suture 

tee 

Teeth-like  structures 

s.b 

Salivary  bulb 

th 

Thickening 

sc 

Scape 

the 

Theca 

s.d 

Salivary  duct 

to 

Torma  or  tormae 

s.e.s 

Stem  of  the  epicranial  suture 

t.th 

Tentorial  thickening 

si 

Sigma   (sclerite) 

V 

Vertex 

233]  HEAD    OF  DIPTERA— PETERSON  63 


PLATE  I 


64  ILLINOIS  BIOLOGICAL  MOSOGRAPHS  [234 


EXPLANATION    OF    PLATE 
Cephalic  Aspect  of  the  Head  and  Mouth-parts 


Fig. 

I. 

Hj'potlietical  head. 

Fig. 

2. 

Simulium  vcnustum ,   female. 

Fig. 

3- 

Simulium  johannseni,  male. 

Fig. 

4- 

Bibiocephala  elcgantula,  male. 

Fig. 

s. 

Bibiocephala  elegantula,  female. 

Fig. 

6. 

Rhabdophaga  strobiloides. 

Fig. 

7- 

Mycctobia  divcrgcns. 

Fig. 

8. 

Psychoda  albipennis. 

Fig. 

9- 

Rhyphus  punctatus. 

Fig. 

10. 

Psorophora  ciliata,  female. 

Fig. 

II. 

Mycctophila  punctata,  female. 

Fig. 

12, 

Chironomus  ferrugineovittatus,  female. 

Fig. 

13- 

Bibio  femorattis,  male. 

Fig. 

14- 

Bibio  femoratus,  female. 

Fig. 

IS- 

Ptychoptcra  rufocincta. 

Fig. 

1 6. 

Trichoccra  bimacula. 

Fig. 

17- 

Sciara  varians. 

Fig. 

i8. 

Tipula  bicornis. 

< 


ILUXOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME 


"^'"         @ 


PETERSOX  HEAD  AND  MOUTH   PARTS  OF  DIPTERA  PLATE  I 


I 


235]  HEAD    OF   DIPTERA—FETERSOX  65 


PLATE  II 


66  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [236 


EXPLANATION    OF    PLATE 

Cephalic  aspect  of  the  Head 

Fig.  19.  Di.va  clavata. 

Fig.  20.  Tabanus  gigantcus,  female. 

Fig.  21.  Tabanus  gigantcus,  male. 

Fig.  22.  Proiuachus  vertebratus. 

Fig.  23.  Eristalis  tenax,  female. 

Fig.  24.  Eristalis  tenax,  dorsal  end  of  the  tormae. 

Fig.  25.  Eristalis  tenax,  male. 

Fig.  26.  Psorophora  ciliata,  male. 

Fig.  27.  Stratiomyia  apicula,  male. 

Fig.  28.  Stratiomyia  apicula,  female. 

Fig.  29.  Exoprosopa  fasciata. 

Fig.  30.  Mydas  clavatus. 

Fig.  31.  Aphiochacta  agarici. 

Fig.  32.  Platypeza  velutina. 

•Fig.  2i.  Psilocephala  haciuorrhoidalis,  male. 

Fig.  34.  Lcptis  vertebrata,  female. 

Fig.  35.  Lcptis  vertebrata,  male. 

Fig.  36.  Psilocephala  hacmorrhoidalis,  female. 

Fig.  37.  Lonchoptcra   lutea,  female. 

Fig.  38.  PipuncuUts  ciiigulatus,  female. 


IIJJXOIS   BIOLOGICAL   MOXOCRAPHS 


rOLUME   s 


PETERSON  HEAD  AND  MOUTH  PARTS  OF  DIPTERA        PLATE  H 


* 


237]  HEAD    OF   DIPTERA— PETERSON  67 


PLATE  III 


68  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [238 


EXPLANATION    OF    PLATE 
Cephalic  Aspect  of  the  Head 

Fig.  39.  Pipunculus  cingulatus,  male. 

Fig.  40.  Empis  clausa,  female. 

Fig.  41.  Scenopinus  fenestraUs,  male. 

Fig.  42.  Scenopinus  fencstralis,  female. 

Fig.  43.  Dolichopus  bifractus. 

Fig.  44.  Calobata  univitta. 

Fig.  45.  Drosophila  ampelophila. 

Fig.  46.  Sepsis  violacea. 

Fig.  47.  Desmometopa  latipes. 

Fig.  48.  Oecothea  fcnestralis. 

Fig.  49.  Heteroneura  flaviseta. 

Fig.  50.  Chyromya  concolor.         , 

Fig.  51.  Chloropisca  glabra. 

Fig.  52.  Sphyraccphala  hrcvicornis. 

Fig.  53.  Oncodes  costatus. 

Fig.  54.  Gastrophilus  equi. 

Fig.  55.  Tetanocera  pluntosa. 

Fig.  56.  Ochthera  mantis. 

Fig.  57.  Oljersia  ardeae. 


ILLIXOIS   BIOLOGICAL    MOXOGRAPHS 


VOLUME  3 


PETERSON         HEAD  AND  MOUTH  PARTS  OF  DIPTERA        PLATE  HI 


239]  HEAD    OF   DIPTERA  — PETERSON  69 


PLATE  IV 


ILLINOIS  BIOLOGICAL  MOXOGRAPHS 


[240 


EXPLANATION    OF    PLATE 


Fig 

58 

Fig 

59 

Fig 

60 

Fig 

61 

Fig 

62 

Fig 

63 

Fig 

64 

Fig 

65 

Fig 

66 

Fig 

67 

Fig 

68 

Fig 

69 

Fig 

70 

-Fig 

71 

Fig 

72 

Cephalic  Aspect  of  the  Head 

Coclopa  vanduzeii. 
Loxocera  pectoralis. 
Saproiiiy::a  vulgaris. 
Euaresta  aequalis. 
Scatophaga  furcata. 
Borborus  equiims. 
Cbrysoviysa  dcmandata. 
Thelaira  leucosona. 
Sarcophaga  haeiiwrrhoidalis. 
Conops  hrachyrhynchns. 
Archytas  aiialis. 
Hydrotaea  dentipcs,  female. 
Hydrotaea  dentipes,  male. 
Musca  domestica,  female. 
Miisca  domestica,  male. 


ILLIXOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME   s 


PETERSOX        HEAD  AND  MOUTH  PARTS  OF  DIPTEKA  PLAll-;  IV 


I 


241]  HEAD    OF   DIPTERA— PETERSON 


PLATE  V 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[242 


EXPLANATION  OF  PLATE 


Fig 

73 

Fig 
VFig 

74 
75 

Fig 

76 

Fig 

77 

Fig 

78 

Fig 

79 

Fig 

8o 

Fig 

8i 

Fig 

82 

Fig 

83 

Fig 

84 

Fig 

8S 

Fig 

86 

Fig 

87 

Fig 

88 

Fig 

89 

Fig 

90 

Caudal  Aspect  of  the  Head 

Hypothetical  head. 

Tabanus  giganteus,  female. 

Tnbanus  giganteus,  male. 

Bibiocephala  clegantula,  male. 

Simuiium  venustum,  female. 

Trichocera  bimacula. 

Dixa  clavata. 

Rhyphus  functatus. 

Sciara  varians. 

Psyclioda  albipennis. 

Bibiocephala  elegantula,  female. 

Promachus  vertebratus. 

Bittaconwrpha  clavipes. 

Rhabdophaga  strobiloides. 

Mycetophila  punctata. 

ChiroHOmus  ferrugineovittatus. 

Chirono)nus  ferrugineovittatus,  dorsal  aspect. 

Mycetobia  divergens. 


ILLIXOIS   BIOLOGICAL    MOXOGRAPHS 


VOLUME   3 


PETERStJX         IIKAIJ  AM)  .MOUIll  PARTS  OF  DIPTERA  PLATE    V 


243]  HEAD    OF   DIPTERA—PETERSOX  73 


PLATE  VI 


74 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[244 


Fig. 

91 

Fig. 

92 

Fig. 

93 

Fig. 

94 

Fig. 

95 

Fig. 

96 

Fig. 

97 

Fig. 

98 

Fig. 

99 

Fig. 

100 

Fig. 

lOI 

Fig. 

102 

Fig. 

103 

Fig. 

104 

Fig. 

105 

Fig. 

106 

Fig. 

107 

Fig. 

108 

Fig. 

109 

Fig. 

110 

Fig. 

III 

Fig. 

112 

EXPLANATION    OF    PLATE 
Caud.\l  Aspect  of  the  Head 

Bibio  femoratus,  male. 

Bibio  femoratus,  female. 

Limnobia  immatura. 

Sphyracephala  brcvicornis.  , 

Tiptila  bicornis. 

Psorophora  ciliata,  female. 

Enipis  clausa,  female. 

Exoprosopa  fasciata. 

Mydas  clavatus. 

Psilocephala  haeiuorrhoidalis,  female. 

Ochthera  mantis. 

Lonchoptera  Iiitea,  female. 

Leptis  vertcbrata,  male. 

Stratiomyia  apicula.  male. 

Oncodes  costatus. 

Pipuncuhis  cingiilatus,  female. 

Scenopinus  fenestralis. 

Dolichopus  sp. 

Oncodes  costatus.  ventral  aspect. 

Platypeca  vclutina. 

Aphiochaeta  agarici. 

Dolichopus  bifractits,  lateral  margins  incomplete. 


ILLIXOIS    niOLOCICAI.    MOXOGR'.irilS 


■  GLUME   3 


PE'lT-RSOX         lll'.AI)  AM)  AKil'l  II    I'AKTS  ol'  DIl'TCKA  i'l.AI  I-:  \'l 


245]  HEAD    OF  DIPTERA— PETERSON  75 


PLATE  VII 


76 


ILLINOIS  BIOLOGICAL  MOXOCRAPHS 


[246 


EXPLANATION    OF    PLATE 
Caudal  Aspect  of  the  Head 


Fig. 

IS- 

Eristalis tenax,  female. 

Fig. 

M- 

Calobata  univitta. 

Fig. 

IS. 

Sapromysa  vulgaris. 

Fig. 

i6. 

Lispa  nasoni,  margin  incomplete. 

Fig. 

17. 

Conops  brachyrhynclius. 

Fig. 

18. 

Sepsis  violacea. 

Fig. 

19- 

Tetanocera  plumosa. 

Fig. 

20. 

Myiospila  meditabunda,  margin  incomplete 

Fig. 

21. 

Coelopa  vandiiscii. 

Fig. 

22. 

Chiromya  concolor. 

Fig. 

23- 

Loxocera  pectoralis. 

Fig. 

24. 

Archytas  analis. 

Fig. 

25. 

Drosophila  ampclophila. 

Fig. 

26. 

Heteroneura  flaviseta. 

Fig. 

27. 

Hydro taea  dentipes. 

Fig. 

28. 

Thelaira  leucozona. 

Fig. 

29- 

Desmomctopa  latipes. 

Fig. 

30. 

Sarcophaga  hacmorrhoidalis. 

Fig. 

31- 

Euarcsta  aeqtialis. 

Fig. 

32. 

Chloropisca  glabra. 

Fig. 

33- 

Musca  domestica,  female. 

Fig. 

34- 

Chrysoniyza  demandata. 

Fig. 

35- 

Scatophaga  furcata. 

Fig. 

36. 

Borborus  equinus. 

ILLIXOIS   BIOLOGICAL    MOXOGRAPHS 


VOLUME   3 


PETHRSOX         11I-.\I)   AM)   MOITH   PARTS   OF   DIPTF.RA       PLA'l  I'.  \'II 


247]  HEAD    OF   DIPTERA— PETERSON  77 


PLATE  VIII 


78 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS 


[248 


EXPLANATION    OF    PLATE 

Caudal  and  Lateral  Aspects  of  the  Head  and  the  Tentorium 

Oecothea  fenestralis,  caudal  aspect. 

Gasirophilus  cqui,  caudal  aspect. 

Olfersia  ardcac.  caudal  aspect. 

Hypothetical  head,  lateral  aspect. 

Hypothetical  tentorium,  lateral  aspect. 

Tabunus  giganleus,  female,  lateral  aspect. 

Tabanus  giganteus,  lateral  aspect  of  the  tentorium. 

Siitniliuiii  vcnustum,  female,  lateral  aspect. 

Leptis  vcrtebrata,  male,  lateral  aspect. 

Mydas  clavatus,  lateral  aspect. 

Promachus  vertebratus,  lateral  aspect. 

Promachus  vertebratus,  lateral  aspect  of  the  tentorium. 

Scenopinus  fenestralis,  female,  lateral  aspect. 

Sciara  variaus,  lateral  aspect. 

Pipunculus  cingulatns,  lateral  aspect. 

Chironoinus  fcrrugincovittatus,  lateral  aspect. 

Bibio  feiiioratus,  female,  lateral  aspect. 

Bibio  fciijoratus,  male,  lateral  aspect. 


Fig. 

37- 

Fig. 

38. 

Fig. 

39 

Fig. 

40. 

Fig. 

41 

Fig. 

42 

Fig. 

43 

Fig. 

44 

Fig. 

45 

Fig. 

46 

Fig. 

47 

Fig. 

48 

Fig. 

49 

Fig. 

SO 

Fig. 

51 

Fig. 

52 

Fig. 

53 

Fig. 

54 

I 


ILLISOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME   3 


'F/rERSON        HEAD  AND  MOUTH  PARTS  OF  DIPTERA       PLATE  VIII 


-249]  HEAD    OF  DIPTERA  —  PETERSOX  79 


PLATE  IX 


80 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS 


[250 


EXPLANATION    OF    PLATE 


?AL  Aspect  of  the  Head  showing  the  Tentorium 

Fig. 

155 

Bibioccphala  elegantula,  female. 

Fig. 

156 

Bibiocephala  elegantula,  male. 

Fig. 

157 

Rhyphus  punctatiis. 

Fig. 

158 

Trkhocera  biiiiacula. 

Fig. 

159 

Psorophora  ciliata,  female. 

Fig. 

160 

Stratioinyia  apiciila,  male. 

Fig. 

161 

Mycetobia  divergcns. 

Fig. 

162 

Exoprosopa  fascia  ta,  eye  removed. 

Fig. 

163 

Dixa  clavata. 

Fig. 

164 

Eiiipis  clav.sa,  female. 

^ig. 

165 

Platypcza  velutina. 

-Mg. 

166 

Psychoda  albipennis. 

Fig. 

167 

Eristalis  tcnax,  female,  eye  removed. 

Fig. 

168 

Dolichopus  bifractus,  eye  removed. 

Fig. 

169 

Loxocera  pectoralis. 

Fig. 

170 

Rhabdophaga  strobiloides. 

Fig. 

i/l 

Saprowyza  vulgaris. 

Fig. 

172 

Drosophila  ampclnphila. 

Fig. 

173 

Psilocephala  haemorrlwidalis,  female. 

Fig. 

174 

Aphiochaeta  agarici. 

Fig. 

175 

Euaresta  acqualis. 

Fig. 

176 

Heteroneura  flaviseta. 

Fig. 

177 

Lonchoptera  lutea. 

Fig. 

178 

Tipula  bicornis. 

Fig. 

179 

Chyromya  concolor. 

ILLINOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME   3 


PMIHRSOX         llF.Al)  AXD   AIOL'Jll    PARTS  OF  DIPTERA        PLATE  IX 


251]  HEAD    OF   DIPTERA— PETERSON 


PLATE  X 


82 


ILLIXOIS  BIOLOGICAL  MOKOCRAPHS 


[2S2 


EXPLANATION    OF    PLATE 
Lateral  Aspect  of  the  Head  showing  the  Tentorium 

Fig.  l8o.  I'etanocera  pluinosa. 

Fig.  i8i.  Chrysoiuy^a  deiitandala. 

Fig.  182.  Coelopa  vanduseii. 

Fig.  183.  Calobata  univitta. 

Fig.  184.  Sepsis  violacea. 

Fig.  185.  DcsiiwiJictopa  latipes. 

Fig.  186.  Conops  brachyrhynchus. 

Fig.  187.  Ochtherti  iiianlis. 

Fig.  188.  Borbnrus  cquinus. 

Fig.  189.  Chloropisca  glabra. 


Fig.  iQph.  Hypothetical  antenna. 

Fig.  199.  Dixa  clavata. 

Fig.  200.  Trichocera  bimacula. 

Fig.  201.  Rhabdophaga  strobiloides. 

Fig.  202.  Psychoda  aWipennis. 

Fig.  203.  Bibiocephala  elcgantula. 

Fig.  204.  Simuliuiu  venustum. 

Fig.  205.  Sciara  zarians. 


Fig. 

190 

Sphyraccphala  brcvicornis. 

Fig. 

191 

Sarcophaga  haenwrrhoidalis. 

Fig. 

192 

Occothea  fciiestralis. 

Fig. 

193 

Scatophaga  furcata. 

Fig. 

194 

Musca  domestica. 

Fig. 

195 

Hydrotaca  dentipes. 

Fig. 

196 

Tliclaira   leucocona. 

Fig. 

197 

Arcbytas  analis. 

Fig. 

198 

Olfcrsia  ardeae. 

INAE 

Fig. 

206 

Chironoinus  fcrrugiiteovitta 
tiis,  female. 

Fig. 

207 

Chironoinus  ferrugin  eovitta 
tus,  male. 

Fig. 

208 

Bihio  fei'ioratus,  female. 

Fig. 

209 

Rliyphus  punctatus. 

Fig. 

210 

Psorophora  ciliata,  female. 

Fig. 

211 

Psorophora  ciliata,  male. 

ILLIXOIS   BIOLOGICAL   MOXOGRAPHS 


VOLUME   s 


i'I-:i  KKSOX         HEAD  AND  .MOUTH   PARTS  OF  DIPTERA  PLATE  X 


253]  HEAD    OF   DIPTERA  —  PETERSOX  83 


PLATE  XI 


84 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[254 


EXPLANATION    OF    PLATE 


Antennae 

Fig.  212.  Mydas  clavatnis.  Fig.  231. 

Fig.  213.  Stratioinyia  apicula.  Fig.  232. 

Fig.  214.  Tabanus  giganteus.  Fig.  233. 

Fig.  215.  Empis  clausa.  Fig.  234. 

Fig.  216.  Exoprosopa  fasciata.  Fig.  235. 

Fig.  217.  Proinachus  vcrtehratus.  Fig.  236. 

Fig.  218.  Leptis  vertebra  ta.  Fig.  237. 

Fig.  219.  Scenopinus  fcnestralis.  Fig.  238. 

Fig.  220.  Oncodes  costatus.  Fig.  239. 

Fig.  221.  Conops   brachyrhynchus.  Fig.  240. 

Fig.  222.  Platypeca  velutina.  Fig.  241. 

Fig.  223.  Lonchoptera  lutea.  — ^Fig.  242. 

Fig.  224.  Aphiochaeta  agarici.  Fig.  243. 

Fig.  225.  Tetanocera  plumosa.  Fig.  244. 

Fig.  226.  Dolichopus  bifratitus.  Fig.  245. 

Fig.  227.  Oecothea  fcnestralis.  Fig.  246. 

Fig.  228.  Desinouiciopa  latipes.  Fig.  247. 

Fig.  229.  Heteronatra   flaviscta.  Fig.  248, 

Fig.  230.  Thelaira  levccozona.  Fig.  249. 

Mandibles 

Fig.  250.  Siiiiuliuiii  venustuni,  female.  Fig.  254. 

Fig.  251.  Psorophora  cUiata,  female.  Fig.  255. 

Fig.  252.  Simuliuin  johannseni,  male.  Fig.  256. 

Fig.  253.  Culicoidcs  sanguisugus, 
female. 


Borborus  equinus. 
Eristalis  tena.v. 
Chyromya  coiicolor. 
Sepsis  violacea. 
Loxocera  pectoralis. 
Calobata   univitta. 
Ochthera  mantis. 
Drosophila   ainpelophila. 
Gastrophilus  cqui. 
Euaresta  aequalis. 
Hydrotaea  dcntipes. 
Musca  doinestica. 
Pipunculus   cingulatus. 
Sarcophaga  haemorrhoidalis. 
Chrysomysa   demandata. 
Scatophaga  furcota. 
Archytas  analis. 
Sapromyca  vulgaris. 
Olfersia  ardeae. 


Di.va  modesta,  female. 
Tabanus  giganteus,  female. 
Bibiocephala   elegantula, 
female. 


ILUNOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


---tf^jB^ 


226  Dc„,.of„.  ^-     \;        ;      245 

227  (v,c,t„    (W5        /      244 


PETERSON"         HEAD  AND  MOUTH  PARTS  OF  DIPTERA  PLATE  XI 


255]  HEAD    OF   DIPTERA— PETERSON  85 


PLATE  XII 


86  ILLISOIS  BIOLOGICAL  MONOGRAPHS  [2S& 


EXPLAN'ATION    OF    PLATE 

Mandible  and  Maxillae 

Fig.  256I1.  Hypothetical  mandible. 
Fig.  257.     Hypothetical  maxillae. 

Siiniiliuin  venustuiii,  female,  cephalic  aspect. 

Tabaitus  giganteus,  female,  caudal  aspect. 

Trichoccra  bimanda,  caudal  aspect. 

Rliyphus  punctatus,  caudal  aspect. 

Di.v(i  clavata,  caudal  aspect. 

Psychoda  albipennis,  caudal  aspect 

Bibio  fenwratus,  caudal  aspect. 

CuUcoidc's  satiguisugus,  female,  caudal  aspect. 

Psorophora  ciliata,  female  and  male,  caudal  aspect. 

Sciara  varians,  caudal  aspect. 

Rhabdophaga  strobiloidcs,  caudal  aspect. 

Bibiocephala  eleganiula,  female,  caudal  aspect. 

Chironomus  ferriigiveovittatus,  cephalic  aspect. 

Mydas  clavatus,  lateral  aspect. 

Platypeza  veluiina,  lateral  a^spect. 

Stratioiiiyia  apicuhi,  cephalic  aspect. 

Einpis  clausa.  lateral  aspect. 

Lcptis  vertebrata,  caudal  aspect. 

Promachus  vcrtebratus,  caudal  aspect. 

Tipula  bicoriiis,  portion  of  caudal  aspect. 

Aphiochaeta  agarici,  lateral  aspect. 

Pipunculus  cingulatus,  lateral  aspect. 

Lonchoptera  lutea. 

Psiloccphala   haenwrrhoidalis,   cephalic   aspect. 

Scenopinits  fenestralis. 

Tabaiius  giganteus,  male,  caudal  aspect. 

Dolichopus  bifractus. 


Fig. 

258. 

Fig. 

259. 

Fig. 

260. 

Fig. 

261. 

Fig. 

262. 

Fig. 

263. 

Fig. 

264. 

Fig. 

265. 

Fig. 

266. 

Fig- 

267. 

Fig. 

268. 

Fig. 

269. 

Fig. 

270. 

Fig. 

271. 

Fig. 

272. 

Fig. 

273. 

Fig. 

274. 

Fig. 

275- 

Fig. 

276. 

Fig. 

277- 

Fig. 

278. 

Fig. 

279- 

Fig. 

280. 

Fig. 

281. 

Fig. 

282. 

Fig. 

283. 

Fig. 

284. 

ILLIXOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


279  Pipuna>l 


PETERSON        HEAD  AND  MOUTH  PARTS  OF  DIPTERA        PLATE  XH 


257]  HEAD    OF   DIPTERA— PETERSON  87 


PLATE  XIII 


ILLINOIS  BIOLOGICAL  MONOGRAPHS  [258 


EXPLANATION    OF    PLATE 
Maxillae 

Fig.  284a.  Eidonchus  tristis. 

Fig.  285.  E.xoprosopa  fasciata. 

Fig.  286.  Eristalis  tenax. 

Fig.  287.  Sepsis  violacca. 

Fig.  288.  Coelopa  vandu:eii. 

Fig.  289.  Saproviysa  vulgaris. 

Fig.  290.  Oecotliea  fenestralis. 

Fig.  291.  Drosophila  ainpeiophila. 

Fig.  292.  Euarcsta  aegualis. 

Fig.  293.  Sphyracephala  brevicornis. 

Fig.  294.  Borborus  equinus. 

Fig.  295.  Chrysomyza  deniandata. 

Fig.  296.  Calobata  univitta. 

Fig.  297.  Ochthera  mantis. 

Fig.  298.  Hetcroneura  flaviseta. 

Fig.  299.  Chyromya  concolor. 

Fig.  300.  Loxocera  pectoralis. 

Fig.  301.  Thelaira  leucocona. 

Fig.  302.  Tctanoccra  pluiiwsa. 

Fig-  303-  Dcsinometopa  latipes. 

Fig.  304.  Musca  domes tica. 

Fig.  305.  Conops  brachyrhynchus. 

Fig.  306.  Chloropisca  glabra. 

Fig.  307.  Scatophaga  furcata. 

Fig.  308.  Hydrotaea  dcntipes. 

Fig.  309.  Archytas  analis. 

Fig.  310.  Sarcophaga  hacniorrhoidalis. 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME   3 


305«Kp  306    /"/         S"4°P1'«*  ,^, 

Conop,  Chloropisca  '^  3U '  3U»  Hydrou.:.  3O9  A„by,„  310s.,cophi«. 


PF.TF.RSOX         HEAD  AND  MOUTH  PARTS  OV  DIPTRRA       PLATF.  XIII 


259]  HEAD    OF   DIPTERA— PETERSON 


PLATE  XIV 


90 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


[26a 


EXPLANATION    OF    PLATE 
Lateral  Aspect  of  the  Mouth-parts  or  Proboscis 


Fig.  311 
Fig.  312 
Fig.  313 
Fig.  314. 
Fig.  31S 
Fig.  316 
Fig.  31 
Fig.  31 
Fig.  319. 
Fig.  320. 
Fig.  321 
Fig.  322 
Fig.  323 
Fig.  324 
Fig.  325 
Fig.  326. 
Fig.  327 
Fig.  328. 
Fig.  329. 
Fig.  330. 
Fig.  331 
Fig.  332 
Fig.  333 


Trichocera  biinacula. 
Chironoimis  ferrugineovittatus. 
Rhabdophaga  strobiloides. 
Sciara  varians. 
Bibio  feiiwratus. 
SimuUum  venustuiii,  female. 
Tabanus  giganteus,  female. 
Psychoda  albipennis. 
Mydas  clavatus. 
Lonchoptera  lutea. 
Rhyphus  punctatus. 
Promachus  vertebratus. 
Leptis  vertehrata. 
Psiloccphala  haeiiiorrlwidalis. 
Scenopinus  fencstralis. 
Platypeza  velutina. 
PipuHculus  cingulattis. 
Eristalis  tenax. 
Sapromyza  vulgaris. 
Desmoiuetopa  latipes. 
Stratiomyxa  apicula. 
Oecothea  fcnestralis. 
Chyroiuya  concolor. 


ILl.IXOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME   3 


327  p,p„„c„iu,       328  E„ 


PETERSON        HEAD  AND  MOUTH  PARTS  OF  DIPTERA       PLATE  XIV 


261]  HEAD    OF  DIPTERA— PETERSON  91 


PLATE  XV 


92  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [262; 


EXPLANATION    OF    PLATE 
Lateral  Aspect  of  the  Proboscis 

Fig-  334-  Sepsis  violacea. 

Fig.  335.  Aphiochaeta  agarici. 

Fig.  336.  Ochthera  mantis. 

Fig.  Z2~.  Coelopa  vanduzeii. 

Fig.  338.  Sphyracephala  brevicornis. 

Fig.  339.  Loxocera  pectoralis. 

Fig.  340.  H ctcroneura  flaviseta. 

Fig.  341.  Chrysoiiiyza  deinandata. 

Fig.  342.  Borborus  eguinus. 

Fig.  343.  Drosophila  ainpelophila. 

Fig.  344.  Tetanoccra  plumosa. 

Fig.  345.  -Chloropisca  glabra. 

Fig.  346.  Thelaira  leucozona. 

Fig.  347.  Euaresta  aequalis. 

Fig.  348.  Calobata  univitta. 

Fig.  34Q.  Hydrotaca  dcntipcs. 


ILLIXOIS   BIOLOGICAL   MOXOGRAPHS 


VOLUME   s 


PETERSON        HEAD  AXD  MOUTH  PARTS  OF  DIPTERA       PLAri'.  X\' 


263]  HEAD    OF   DIPTERA— PETERSON  9i 


PLATE  XVI 


94 


ILLIXOIS  BIOLOGICAL  MOXOCRAPHS 


[264 


EXPLANATION    OF    PLATE 


Fig.  350. 
yFig.  351 
Fig.  352. 
Fig.  353 
Fig.  354. 
Fig.  355 
Fig.  356. 
Fig.  357 
Fig.  3S8. 
Fig.  359 
Fig.  360, 
Figr  361 
Fig.  362 
Fig.  363, 
Fig.  364 
Fig.  364a 
Fig.  365 
Fig.  366. 
Fig.  367, 
Fig.  368, 
Fig.  369, 
Fig.  3-0, 


Mouth-parts 

Siircophaga  haeiitorrhoidalis,  lateral  aspect. 

Miisca  domcstica,  lateral  aspect. 

Einpis  clausa,  lateral  aspect. 

Archytas  analis,  lateral  aspect. 

Stoiiio.rys  calcitrans,  lateral  aspect. 

Sipliona  genicitlata,  lateral  aspect. 

Conops  bracbyrhynchus,  lateral  aspect. 

Scatophaga  furcata,  lateral  aspect. 

Olfersia  ardeae,  lateral  aspect. 

Stylogaster  biannulata,  caudal  aspect. 

Sciara  varians,  maxillae  and  labium,  cephalic  aspect. 

E.voprosopa  fasciata,  lateral  aspect. 

Hypothetical  and  typical  labium,  mesal  aspect. 

Hypothetical  mouth-parts,   lateral  aspect. 

Bibio  fenioratus,  maxillae  and  labium,  cephalic  aspect. 

Eulonchus  tristis,  head   and   mouth-parts,   lateral   aspect. 

Trichocera  biiuacula,  maxillae  and  labium,  cephalic  aspect. 

Sbnulium  venustuni,  maxillae  and  labium,  cephalic  aspect. 

Rhabdophago  strobiloidcs,  maxillae  and  labium,  caudal  aspect, 

Lcia  oblcctabilis,  maxillae  and  labium,  cephalic  aspect. 

Lcptis  vcrtcbrata,   mesal  aspect   of   glossa. 

Leptis  vcrtcbrata,  maxillae  and  labium,  caudal  aspect. 


ILLIXOIS   BIOLOGICAL   MOKOGRAPHS 


VOLUME   3 


PETERSON         HEAD  AND  MOUTH  PARTS  OF  DIPTERA       PLATE  XVI 


265]  HEAD    OF   DIPTERA— PETERSON  95 


PLATE  XVII 


96  ILUXOIS  lilOLOCICAL  MOXOCRAPHS  [266 


Fig. 

3/1. 

Fig- 

3/2. 

Fig. 

273- 

Fig. 

374. 

Fig. 

375. 

Fig. 

376. 

Fig. 

377- 

Fig. 

378. 

Fig. 

379. 

EXPLANATION    OF    PLATE    . 
Maxillae  and  Labium 

Chirononnis  fcrriiyineovittatus,  cephalic  aspect. 

Psyclioda  albi/'cnins,  cephalic  aspect. 

Psoro/'liora  ciliata,  female,  portions  of  mandibles,  maxillae,  labium,  ten- 
torium, and  head-capsule. 

Rhyphus  puiictatus,  cephalic  aspect. 

Di.va  davata,  cephalic  aspect. 

Proinachus  vertcbratus,  caudal  aspect. 

Proiiiachus  vcrtehratus,  labium,  ceplialic  aspect. 

Proinachus  vcrtehratus,  cross-section  of  labium,  see  figure  377. 

Proinachus  vcrtehratus,  distal  end  of  labium,  cephalic  aspect. 
Fig.  380.     Psorophora  ciliata,  distal  end  of  labium,  caudal  aspect. 
Fig.  381.     Psorophora  ciliata,  distal  end  of  labium,  cephalic  aspect. 
Fig.  382.     Geranoinyia  canadensis,  cephalic  aspect. 
Fig.  383.     Tipula  bicornis,  distal  end  of  labium,  mesal  aspect. 
Fig.  384.     Tipula  bicornis,  caudal  aspect  of  labium. 
Fig.  385.     Hclobia  punctipennis,  caudal  aspect. 
Fig.  386.     Limnobia  innnatura,  caudal  aspect. 
Fig.  387.     Dixa  clavala.  caudal  aspect  of  labium. 

Fig.  388.     Tipula  bicornis,  sclerites  about  distal  end  of  theca  of  labium. 
Fig.  389.    Bittacomorpha  clavipcs,  distal  end  of  labium,  mesal  aspect. 
Fig.  390.     Tabanus  gigantcus,  mesal  aspect  of  labium. 
Fig.  391.     Tabanus  giganteus,  caudal  aspect  of  labium. 
Fig.  392.     Tabanus  giganteus,  cephalic  aspect  of  labium. 
Fig.  393.     Aphiochacta  agarici,  caudal  aspect. 
Fig.  394.     Aphiochacta  agarici,  distal  end  of  labium,  mesal  aspect. 


II.LIXOIS   BIOLOGICAL   MONOGRAPHS 


VOLl'ME   3 


PETERSON        HEAD  AND  MOUTH  PARTS  OF  DIPTERA     PLATE  XVH 


267]  HEAD    OF   DIPTERA—PETERSOX  97 


PLATE  XVIII 


ILLIXaS  BIOLOGICAL  MOXOGRAPHS  [26S 


EXPLANATION    OF    PLATE 
Labium 

Fig.  395.  Stratioiiiyia  apicula,  caudal   aspect  of  proboscis. 

Fig.  396.  Stratioiiiyia  apicula,  mesal  aspect. 

Fig.  397.  Mydas  clavatus,  caudal  aspect. 

Fig.  398.  Mydas  clavatus,  cephalic  aspect. 

Fig.  399.  Bibioccphala   elcgantiila,  cephalic  aspect. 

Fig.  400.  Scenopinus  fencstralis,  mesal  aspect. 

Fig.  401.  Scenopinus  fenestralis,  caudal  aspect. 

Fig.  402.  Psilocepltala  hacmorrhoidalis,  caudal  aspect. 

Fig.  403.  Psilocepltala  hacmorrhoidalis,  mesal  aspect. 

Fig.  404.  Desiiioiuetopa  latipcs,  caudal  aspect. 

Fig.  405.  Desiiioiuetopa  latipcs,  cephalic  aspect. 

Fig.  406.  Lonchoptera  lutea,  caudal  aspect. 

Fig.  407.  Lonchoptera  lutea,  cephalic  aspect. 

Fig.  408.  Lonchoptera  lutea,  mesal  aspect. 

Fig.  4,09.  Saproinyso  vulgaris,  caudal  aspect. 

Fig.  410.  Saproinyca  vulgaris,  mesal  aspect. 

Fig.  411.  Chyroiiiya  concolor,  caudal  aspect. 

Fig.  412.  Chyroniya  concolor,  mesal  aspect. 

Fig.  413.  Euaresta  aequalis,  caudal  aspect. 

Fig.  414.  Euaresta  aequalis,  mesal  aspect. 

Fig.  415.  Platypeca  velutina,  mesal  aspect. 

Fig.  416.  Platypesa  velutina,  caudal  aspect. 

Fig.  417.  Conops  brachyrhynchus.  distal  end.  caudal  aspect. 

Fig.  418.  Conops  brachyrhynchus,  distal  end,  lateral  aspect. 

Fig.  419.  Conops  brachyrhynchus,  distal  end,  cephalic  aspect. 

Fig.  420.  Conops  brachyrhynchus,  caudal  aspect. 

Fig.  421.  Eiiipis  clausa,  caudal  aspect. 

Fig.  422.  Eiiipis  clausa,  portion  of  cephalic  aspect. 

Fig.  423.  Eiiipis  clausa,  cephalic  aspect. 

Fig.  424.  Rhainphoniyia  glabra,  caudal  aspect. 

Fig.  425.  Rhainphoniyia  glabra,  mesal  aspect. 

Fig.  425a.  Eulonchus  tristis,  cephalic  aspect. 

Fig.  425b.  Eulonchus  tristis,  distal  end,  mesal  aspect. 

Fig,  426.  Exoprosopa  fasciata,  distal  end,  caudal  aspect. 

Fig.  427.  Exoprosopa  fasciata,  cephalic  aspect. 

Fig.  428.  Exoprosopa  fasciata,  distal  end,  mesal  aspect. 

Fig.  429.  Exoprosopa  fasciata,  caudal  aspect. 


ILUXOIS   BIOLOGICAL   MONOGRAPHS 


rOLCME   s 


Einpi*  Rh«mphomy  a 

483  424  426 


427        428         4ie 


PETERSON         HEAD  AND  .MOUTH  PARTS  OF  DIPTERA     PLATE  W 


269]  HEAD    OF  DIPTERA— PETERSON  99 


PLATE  XIX 


100  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [270 


EXPLANATION    OF    PLATE 
Labium 

Fig.  430.  Chloropisca  glabra,  caudal  aspect. 

Fig.  431.  Chlorofisca  glabra,  cephalic  aspect. 

Fig.  432.  Dolichopus  bifractus,  mesal  aspect. 

Fig.  433.  Dolichopus  bifractus,  caudal  aspect. 

Fig.  434.  Dolichopus  bifractus.  lateral  aspect. 

F'g-  435-  Pipunculus  cingulatus,  caudal  aspect. 

Fig.  436.  Pipunculus  cingulatus,  cephalic  aspect. 

Fig-  437-  Borborus  cquinus,  caudal  aspect. 

Fig.  438.  Borborus  equinus,  mesal  aspect. 

Fig.  439.  Sepsis  violacea,  caudal  aspect. 

Fig.  440.  Sepsis  violacea,  mesal  aspect. 

Fig.  441.  Eristalis  tenax,  mesa!  aspect. 

Fig.  442.  Eristalis  tenax,  caudal  view. 

Fig.  443.  Eristalis  tenax,  distal  end  of  theca,  caudal  aspect. 

Fig.  444.  Ochthera  mantis,  caudal  aspect. 

Fig.  445.  Ochthera   mantis,  mesal  aspect. 

Fig.  446.  Calobata  univitta,  mesal  aspect. 

Fig.  447.  Calobata  univitta,  caudal  aspect. 

Fig.  448.  Coelopa  vanduzcii,  caudal  aspect. 

Fig.  449.  Coelopa  vandu:cii,  mesal  aspect. 

Fig.  450.  Sphyracephala  brcvicornis,  caudal  aspect. 

Fig.  4SI.  Sphyracephala  brevicornis,  mesal  aspect. 

Fig.  452.  Oecothea  fenestralis,  caudal  aspect. 

Fig.  453.  Oecothea  fenestralis,  mesal  aspect. 

Fig.  454.  Drosophila  ampclophila,  caudal  aspect. 

Fig.  455.  Drosophila  ampclophila,  mesal  aspect. 

Fig.  456.  Chrysomyca  demandata,  mesal  aspect. 

Fig.  457.  Chrysomyca  demandata,  caudal  aspect. 

Fig.  458.  Siphona  geniculata,  distal  end,  cephalic  aspect. 


ILLISOIS    BIOLOGICAL   MOXOGRAPHS 


VOLVME   .? 


PETERSON'         HEAD  AND  MULTll   PARTS  OF  DIPTERA       PLATE  XIX 


271]  HEAD    OF   DIPTERA  — PETERSON  101 


PLATE  XX 


102  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [272 


EXPLANATION    OF    PLATE 
Labium  and  other  Parts 

Fig.  459.  Heteroneura  ftaviseta,  caudal  aspect. 

Fig.  460.  Heteroneura  flaviseta,  mesal  aspect. 

Fig.  461.  Loxocera  pectoralis,  caudal  aspect. 

Fig.  462.  Loxocera  pectoralis,  mesal  aspect. 

Fig.  463.  Tetanocera  plumosa,  caudal  aspect. 

Fig.  464.  Tetanocera  plumosa,  mesal  aspect. 

»^  Fig.  465.  Musca  domestica,  dorsal  aspect  of  glossae. 

Fig.  466.  Musca  domestica,  caudal  aspect. 

Fig.  467.  Musca  domestica,  mesal  aspect. 

Fig.  468.  Archytas  analis,  caudal  aspect. 

Fig.  469.  Archytas  analis,  mesal  aspect. 

Fig.  470.  Scatophaga  furcata,  caudal  aspect  of  mediproboscis. 

Fig.  471.  Scatophaga  furcata,  ventral  aspect  of  distiproboscis. 

Fig.  472.  Scatophaga  furcata,  mesal  aspect. 

Fig.  473.  Thelaira  leucosona,  caudal  aspect. 

Fig.  474.  Thelaira  leucocona,  mesal  aspect. 

Fig.  475.  Hydrotaca  dcntipes,  caudal  aspect. 

Fig.  476.  Hydrotaea  dentipes,  mesal  aspect. 

Fig.  477.  Sarcophaga  haeniorrhoidalis,  caudal  aspect. 

Fig.  478.  Sarcophaga  haemorrhoidalis.  mesal  aspect. 

Fig.  479.  Stonwxys  calcitrans,  distal  end.  lateral  aspect. 

Fig.  480.  Stonwxys  calcitrans,  distal  end>  mesal  aspect. 

Fig.  481.  Lispa  nasoni,  distal  end,  mesal  aspect. 

Fig.  482.  Bombylius   major,   cross-section   tbru   pseudotrachea.      (After 

Dimmock.) 

Fig.  483.  Ochthera  mantis,  cross-section  thru  pseudotrachea. 

Fig.  484.  Musca  (Calliphora)  voinitoria,  cross-section  thru  pseudotrachea 

(After   Dimmock.) 

Fig.  485.  Musca  (Calliphora)  romitoria,  an  enlarged  pseudotrachea.     (After 

Dimmock.) 

Fig.  486.  Oncodcs  costattts,  entire  mouth-parts,  caudal  aspect. 

Fig.  487.  Oncodes  costatus,  entire  mouth-parts,  lateral  aspect. 

Fig.  488.  Olfersia  ardeae,  distal  end,  lateral  aspect. 

Fig.  489.  Siinulium  venustuni,  cephalic  aspect  of  the  labrum. 

Fig.  490.  Gastrophilus  equi,  entire  mouth-parts,  caudal  aspect. 

Fig.  491.  Gastrophilus  equi,  sagittal  section  thru  mouth-parts. 

Fig.  492.  Gastrophilus  equi,  entire  mouth-parts,  cephalic  aspect. 


ILLIXOIS   BlOl.OGICAI.   MOXOGR.IPHS 


VOLUME  3 


OncojM  Simiiliiim  Castrophilus  Gasirophilus        Gaslrophflw 

487  489  490  491  492 


I'KTF.RSOX         Ill-.AD   AXD  MOUTH   PARTS  OF  DIPTERA       PI.  \ Tl"  XX 


273]  HEAD    OF  DIPTERA— PETERSON  103 


PLATE  XXI 


104 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[274 


\ 


EXPLANATION   OF    PLATE 

EpfPHARYNX    AND   HyPOPHARYNX    AND   ASSOCIATED    PARTS 

Hypothetical  type,  lateral  aspect. 
Tabanus  giganteus,  female,  lateral  aspect. 
Tabanus  giganteus,  male,  lateral  aspect. 
Tabanus  giganteus,  female,  caudal  aspect. 
Simulium  venustum,  female,  lateral  aspect. 
Siiiiuliuti!  venustum,  female,  caudal  aspect. 
Trichoccra  biniacida,  lateral  aspect. 
Trichoccra  biiiiacula,  caudal  aspect. 
Dixa  clavata,  lateral  aspect. 
Dixa  clavata,  caudal  aspect. 
Tipula  bicornis,  lateral  aspect. 
Psorophora  ciliata,  female,  lateral  aspect. 
Psorophora  ciliata,  female,  caudal  aspect. 
Geranomyia  canadensis,  lateral  aspect. 
Livinobia  inuitatura,  lateral  aspect. 
Rhyphus  punctatus,  lateral  aspect. 
Rhyphus  punctatus.  caudal  aspect. 


Fig 

493 

Fig 

494 

Fig 

495 

Fig 

496 

Fig 

497 

Fig 

498 

Fig 

499 

Fig 

SCO 

Fig 

SOI 

Fig 

502 

Fig 

503 

Fig 

504 

Fig 

505 

Fig 

S06 

Fig 

507 

Fig 

508 

Fig 

509 

ILLISOIS   BIOLOGICAL    MOSOGRAPHS 


VOLUME 


PETi;kSOX         IIF.AI)  AND  MOUTH  TARTS  oi'  HIPTI-KA       \'\.\\V.  XXI 


275]  HEAD    OF   DIPTERA  — PETERSON  105 


PLATE  XXII 


106  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [276 


EXPLANATION    OF    PLATE 

Epipharynx  and  Hyfopharynx  and  Associated  Parts 

Fig.  510.  Rhabdophaga  strohiloides,  caudal  aspect. 

Fig.  511.  Rhabdophaga  strobiloides,  lateral  aspect. 

Fig.  512.  Sciara  varians,  caudal  aspect. 

Fig.  513.  Sciara  varians,  lateral  aspect. 

Fig.  514.  Pcriplaneta  oricntalis,  clypeiis,  labrum,  and  epipharynx  spread  out,  enta! 

aspect. 

Fig.  515.  Melanoplus   diffcrentialis,   clypeus,   labrum.   and   epipharynx   spread   out, 

ental  aspect. 

Fig.  516.  Gryllus  pennsylvanicus,  right-half  of   clypeus,   labrum,  and  epipharynx, 

cephalic  and  caudal  aspects. 

Fig.  517.  Proiiiachus  vcrtebratus,  lateral  aspect. 

Fig.  518.  Promachus  vcrtebratus,  epipharynx  and  labrum,  caudal  aspect. 

Fig.  519.  Promachus  vcrtebratus,  caudal  aspect. 

Fig.  520.  Leptis  vertcbrata,  lateral  aspect. 

Fig.  521.  Culicoides  sanguisugus,  lateral  aspect. 

Fig.  522.  Bibio  fciiwratus,  caudal  aspect. 

Fig-  523.  Bibio  femoratus,  lateral  aspect. 

Fig.  524.  Dolichopus  bifractus,  caudal  aspect. 

Fig.  525.  Leptis  vertcbrata,  caudal  aspect. 

Fig.  526.  Bibioccphala  clcgantula.  caudal  aspect. 

Fig.  527.  Bibioccphala  clcgantula,  lateral  aspect. 

Fig.  528.  Dolichopus  bifractus,  lateral  aspect. 


ILLIXOIS   BIOLOGICAL   MOXOGRAPHS 


VOLUME   3 


Dolichop 

524 


PETERSON'        HEAD  A\D  MOlTll  PARTS  (W  DIPTERA       PLATE  XXIT 


277]  HEAD    OF  DIPTERA— PETERSON  107 


PLATE  XXIII 


108  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [278 


EXPLANATION    OF    PLATE 
Epipharynx  and  Hypopharynx  and  Associated  Parts 

Fig.  529.  Psychoda  albitcitiiis,  lateral  aspect. 

Fig.  530.  Psychoda  albipcunis,  caudal  aspect. 

Fig.  531.  Chironoimis  fcrrugincoziltatiis,  lateral  aspect. 

Fig.  532.  Cliiroiwmus  ferrugincorittatus,  caudal  aspect. 

Fig.  533.  Psilocephala  haemorrhoidalis,  lateral  aspect. 

Fig.  534.  Psilocephala  haemorrhoidalis,  caudal  aspect. 

Fig.  535.  Mydas  clavaius,  lateral  aspect. 

Fig.  536.  Mydas  clavatus,  caudal  aspect. 

Fig.  537-  Scenopinus  fcncstralis,  caudal  aspect. 

Fig.  538.  Scenopinus  fencstralis,  lateral  aspect. 

Fig.  539.  Lonchoptera  lutea,  lateral  aspect. 

Fig.  540.  Aphiochaeta  agarici,  caudal  aspect. 

Fig.  S41.  Lonchoptera  lutea,  caudal  aspect. 

Fig.  542,  Platypesa  vchitina,  caudal  aspect. 

Fig.  542a.  Platypc:a  vclutina.  lateral  aspect. 

Fig.  S43.  Eidonchus  tristis,  lateral  aspect. 

Fig.  S44-  Aphiochaeta  agarici,  lateral  aspect. 

Fig.  545.  Stratiomyia  apicula,  lateral  aspect. 

Fig.  546.  Stratiomyia  apicula,  caudal  aspect. 

Fig.  547.  Em  pis  clausa,  lateral  aspect. 

Fig.  548.  Empis  clausa,  caudal  aspect. 

Fig.  549.  Exoprosopa  fasciata,  lateral  aspect. 

Fig.  550.  Exoprosopa  fasciata.  caudal  aspect. 


n.LIXOlS   BIOLOGICAL   MOXOGRAPHS 


J-OLUME   s 


547  548  549  550 

I'M  1  KRSUX         ili;,\l)  AXIJ  .MUL' III  PARTS  OF  DIPTKRA       PLATF.  XXIII 


279]  HEAD    OF   DIPTERA— PETERSON  109 


PLATE  XXIV 


no 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[280 


EXPLANATION    OF    PLATE 

EpiPHARYNX    AND    HyPOPHARYNX    AND   ASSOCIATED    ParTS 


Fig.  551 
Fig.  552. 
Fig.  553 
Fig.  554. 
Fig.  555 
Fig.  556. 
Fig.  557. 
Fig.  SS8. 
Fig.  559. 
Fig.  560. 
Fig.  561 
Fig.  562 
Fig.  563 
Fig.  564 
Fig.  56s 
Fig.  566. 
Fig.  567 
Fig.  568. 
Fig.  569, 
Fig.  S70. 
Fig.  571 
Fig.  572 
Fig.  573 
Fig.  574 
Fig.  575 
Fig.  576. 
Fig.  5: 
Fig.  578. 
Fig.  579- 


Calobata  univitta,  caudal  aspect. 

Calobata  univitta,  lateral  aspect. 

Sapromyca  vulgaris,  lateral  aspect. 

Saf>roiiiyca  vulgaris,  caudal  aspect. 

Chloropisca  glabra,  caudal  aspect. 

Chloropisca  glabra,  lateral  aspect. 

Chrysomysa  deiiiandata,  caudal  aspect. 

Chrysoinyca  deinandata.  lateral  aspect. 

Coelopa  vanduzeii,  caudal  aspect. 

Coelopa  vanduzeii,  lateral  aspect. 

Pipunculus  cingulatus,  caudal  aspect. 

Pipunculus  cingulatus,  lateral  aspect. 

Drosophila  ampclophila,  caudal  aspect. 

Drosophila  aiupelophila,  lateral  aspect. 

Borborus  equinus,  lateral  aspect. 

Borborus  equinus,  caudal  aspect. 

Borborus  equinus,  liypopharynx  united  with  labium,  caudal  aspect. 

Chyroiiiya  concolor,  caudal  aspect. 

Chyroiiiya  concolor,  lateral  aspect. 

Lo.voccra  pectoraiis,  caudal  aspect. 

Lo.roccra  pectoraiis.  lateral  aspect. 

Euarcsta  acqualis,  caudal  aspect. 

Euaresta  acqualis,  lateral  aspect. 

Ochthera  mantis,  lateral  aspect. 

Ochthera  mantis,  caudal  aspect  of  the  labrum. 

Ochthera   mantis,  caudal  aspect  of  the  epipharynx. 

Ochthera   mantis,  caudal  aspect. 

Dcsmonictopa    latipes,    lateral    aspect. 

Desnio-.uetopa  latipes,  caudal  aspect. 


ILLINOIS   BIOLOGICAL   MONOGRAPHS 


VOLUME   3 


Euvcsta 

EtuKsta 

Ochihcra 

Ochthet. 

Ochthcft 

672 

673 

574 

676 

577 

PETERSON         HEAD  AND  MOUTH  PARTS  UI'  DirXEKA       PLATE  XXIV 


\ 


2811  HEAD    OF  DIPTERA— PETERSON  111 


PLATE  XXV 


112  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [282 

\ 


EXPLANATION   OF   PLATE 

Epipharynx  and  Hypopharynx  and  Associated  Parts 

Fig.  580.  Occothea  fenestralis,  lateral  aspect. 

Fig.  581.  Oecothea  fenestralis,  caudal  aspect. 

Fig.  582.  Sepsis  violacea,  lateral  aspect. 

F'g-  583-  Sepsis  violacea,  caudal  aspect. 

Fig.  584.  Tetanocera  plumosa,  lateral  aspect. 

Fig.  585.  Sphyracephala  hrevicornis,  lateral  aspect. 

Fig.  586.  Tetanocera  plumosa,  caudal  aspect. 

Fig.  587.  Eristalis  tenax,  caudal  aspect. 

Fig.  588.  Eristalis  tenax,  lateral  aspect. 

Fig.  589.  Heteroneura  fiaviseta,  lateral  aspect. 

Fig.  SQO.  Heteroneura  fiaviseta,  caudal  aspect. 

Fig.  591.  Conops  hrachyrhynchus,  caudal  aspect. 

Fig.  592.  Conops  hrachyrhynchus,  lateral  aspect. 

Fig.  593.  Scatophaga  furcata,  lateral  aspect. 

Fig.  594.  Scatophaga  furcata,  caudal  aspect. 

Fig.  595.  Thelaira  lexicosona,  lateral  aspect. 

Fig.  596.  Thelaira  leucozona,  caudal  aspect. 

Fig.  597.  Hydrotaea  dentipes,  lateral  aspect. 

Fig.  598.  Hydrotaea  dentipes,  caudal  aspect. 

Fig.  599.  Stomoxys  calcitrans,  lateral  aspect. 

l/Fig.  600.  Musca  doinestica,  lateral  aspect. 

Fig.  601.  Musca  domestica,  caudal  aspect. 

Fig.  602.  Sarcophaga  haemorrhoidalis,  lateral  aspect. 

Fig.  603.  Sarcophaga  haemorrhoidalis,  caudal  aspect. 

Fig.  604.  Archytas  analis,  lateral  aspect. 

Fig.  605.  Archytas  analis,  caudal  aspect. 

Fig,  606.  Olfcrsia  ardeae,  lateral  aspect. 


ILLIXOIS   BIOLOGICAL   MOSOGRAriiS 


VOLUME   3 


604  606 


PETERSOX        HEAD  AXl)  MOUTH  PARTS  OF  DIPTERA       PLATE  XXV 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 

Vol.111  January,  1917  No.  3 

Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate  School  Bt 

THE  University  of  Illinois 


Copyright,  1917 

By  the  University  of  Illinois 

Distributed  May  5,  1917 


STUDIES  ON  NORTH 

AMERICAN  POLYSTOMIDAE, 

ASPIDOGASTRIDAE,  AND 

PARAMPHISTOMIDAE 


WITH  ELEVEN   PLATES 


HORACE  WESLEY  STUNKARD 


Contributions  (lom  the 
Zoological  Laboratory  o(  the  University  of  Illinois  ander 
the  direction  of  Uenrj  B.  Ward.  No.  »4 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree   of    Doctor  of   Philosophy  in  Zoology 

in  the  Graduate  School  of  the 

University  of  Illinois 

1916 


TABLE  OF  CONTENTS 


PAGE 

Introduction  7 

Polystomidae  _ 9 

Historical   Review  of  the  Fainily g 

The  Genus  Polystoma  i6 

Anatomy  and  Histology  of  the  Polystomidae 19 

Polystoma  orbiculare   Stunkard   1916  31 

Polystoma  opacum   Stunkard    1916  34 

Polystoma  megacotyle  Stunkard   1916  37 

Polystoma  niicrocotyle   Stunkard    1916  39 

Polystoma  coronatum  Leidy   1888 40 

Polystoma  hassalli   Goto   1899   42 

Polystoma  ohlongum   Wright  1879  44 

Key  to  the  Species  of  the  Genus  Polystoma 46 

Aspidogastridae    47 

Aspidogaster  conchicola  von  Baer  1827 48 

Cotylaspis  insignis  Leidy   1856  49 

Cotylaspis  cokeri   Barker  and  Parsons  1914 SO 

Classification  of  the  Family 57 

Parauiphistomidae  60 

Historical   Review  of  the  Family „ 60 

The  Genus  Alassostoma  _ 64 

Alassostonia  magnum  Stunkard   1916 66 

Alassostoma  parvum  Stunkard  1916 69 

Tlie   Genus   Zygocotyle  _ _ 71 

Zygocotyle  ceratosa   Stunkard   igi6. 72 

Classification  of  the  Family 75 

Relation  of  the  Families  to  the  Order 80 

List  of  Xew   Species 84 

Bibliography    85 

Explanation  of  Plates  __ 91 


2871  SORTII  AMERICAS  FOLVSTOMIDAE—STUXKARD 


INTRODUCTION 

The  knoAvledgi'  of  the  trematodes  of  North  America  is  very  scanty. 
Information  at  hand  consists  largely  of  brief  and  scattered  papers  and 
(;omprehensivc  studies  on  the  morphology  of  the  larger  groups  are  want- 
ing. Such  studies  are  needed  as  contributions  to  the  knowledge  of  adult 
forms,  and  it  is  apparent  also  that  knowledge  of  the  anatomy  and  tax- 
onomy of  the  adult  is  demanded  in  the  solution  of  life  history  problems. 

This  paper  contains  the  results  of  a  study  on  the  structure 
and  classification  of  North  American  representatives  of  the  families 
Polystcmidae,  Aspidogastridae,  and  Paramphistomidae.  Because  of  cer- 
tain structural  and  developmental  features  these  three  families  are  of 
particular  interest  and  importance  not  only  in  the  taxonomy  but  also  in 
the  phylogeny  of  the  trematodes.  The  Polystcmidae  differ  fi-om  all  other 
known  Ileterocotylea  in  tliat  tliey  are  endoparasitic ;  the  .\spidogastri- 
dae  are  both  ectoparasitic  and  endoparasitic,  develop  both  directly  and 
by  means  of  an  intermediate  host,  and  in  the  adult  condition  are  pai'a- 
sites  of  both  vertebrates  and  molluscs ;  while  the  Paramphistomidae  are 
the  onl}-  forms  retaining  a  primitive  postei'icr  sucker.  These  facts  are 
significant  and  it  is  probable  that  further  study  into  the  structure  and 
life  history  of  these  forms  will  throw  considerable  light  on  the  general 
jiroblems  of  development  and  taxonomy  of  the  trematodes. 

During  the  past  three  years  the  writer  has  made  parasitological 
examinations  of  over  three  hundred  North  American  fresh-water  turtles. 
These  compri.se  sixteen  species  collected  from  widely  scattered  localities. 
For  assistance  in  securing  tliis  material,  grateful  acknowledgments  are 
due  Dr.  N.  A.  Cobb  of  Washington,  D.  C.  Professor  A.  W.  Orcutt  of 
Denison  University,  Professor  \V.  E.  Burge  of  the  University  of 
Illinois.  Professor  J.  E.  Aekert  of  Kansas  State  Agricultural  College, 
and  Professor  \V.  W.  Cort  of  Macalcster  College.  Tlie  material  of 
Alassostoma  parviim  was  collected  and  turned  over  to  me  by  Mr.  T.  B. 
Magath.  A  type  specimen  of  Pohjstoma  coronaium  Leidy  from  the  U.  S. 
National  Museum  was  placed  at  my  disposal  for  study.  The  work  was 
begun  at  the  suggestion  of  Professor  Henry  B.  Ward  and  carried  on 
under  his  direction.  Part  of  the  material  used  in  the  investigation 
came  from  his  private  collection,  and  for  this  material  as  well  as  for 
criticisms  and  suggestions  in  the  course  of  the  work  the  writer  wishes  to 
express  his  appreciation. 


8.  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [288 

All  the  forms  described  in  tliis  paper  were  studied  as  toto  mounts; 
where  sufficient  material  was  available  sections  were  made,  and  many 
were  studied  alive.  The  importance  of  the  study  of  the  living  specimens 
can  not  be  overemphasized  as  the  best  method  of  tracing  the  excretory 
system.  Also,  by  observing  the  living  animal  as  it  moves,  it  is  possible 
to  measure  the  extent  of  normal  variation  in  form  that  occurs  in  a  single 
specimen  as  different  shapes  are  assumed  concomitant  with  the  move- 
m.ents  of  the  animal ;  in  forms  with  such  soft  bodies  and  variable  shapes, 
a  study  of  preserved  material  alone  has  in  many  eases  given  false  con- 
ceptions concerning  morphological  relationships  of  organs  and  systems. 
In  toto  mounts  a  support  under  the  eoverglass  is  necessary  to  prevent  it 
from  flattening  and  distorting  the  normal  shape  of  the  aspidogastrids 
and  to  avoid  crushing  the  caudal  disc  of  the  poly.stomes.  For  the  stain- 
ing of  specimens  to  be  mounted  in  toto,  better  results  were  obtained  by 
the  use  of  carmine  than  by  hematoxylin  stains.  For  staining  sections 
the  method  that  proved  most  valuable  was  to  use  the  hematoxylin  stains 
for  differentiating  the  nuclear  elements  and  various  plasma  stains  for 
counterstaining. 


XORTH  AMERICAX  POLVSTOMlDAESTrXKARD 


POLYSTOMIDAE 


HISTORICAL  REVIEW  OF  THE  FAMILY 


In  1758  Roesel  von  Rosenhof  described  and  figured  a  "leeeir'  from 
tlie  urinary  bladder  of  the  frog.  Tliis  is  regarded  as  identical  with  the 
well  known  European  parasite  of  the  urinary  bladder  of  the  frog, 
described  by  Frohlich  (1791)  as  Linguatuln  integer rimum.  M.  Braun 
(1792)  described  Planai-ia  uncinulata  from  the  urinary  bladder  of  the 
green  water-frog  and  his  description  is  so  specific  tliat  there  can  be  no 
doubt  that  he  had  the  same  form  described  by  Frohlich  the  previous 
year.  Zeder  (1800)  founded  the  genus  Polystoma  to  contain  the  three 
species,  Linguatula  intcgerrimum  Prohlicli  which  he  rechristened  Pohj- 
stoma  ranac,  P.  serratum,  and  P.  pinguicola.  According  to  Stiles  and 
Hassall  (1908)  the  type  was  clearly  intended  to  be  P.  ranae  =  Plaiiaria 
uuciiivlata,  and  altho  Braun  had  described  the  form  correctly  with  the 
suckers  and  hooks  at  the  posterior  end  of  the  body,  Zeder  erroneously 
stated  in  liis  characterization  of  the  geuus  that  the  suckers  were  at  the 
anterior  end.  P.  serratum  had  been  designated  by  Frohlich  (1789)  as 
type  of  the  genus  Linguatula  and  P.  pinguicola  had  been  designated  by 
Treutler  (1793)  as  type  of  the  genus  Ile.xathyridium.  That  Zeder  was 
in  error  in  including  these  species  in  the  genus  Polystoma  was  demon- 
strated by  later  studies.  However  Rudolphi  (1809)  retained  them  in  the 
genus  Polystoma  and  listed  three  other  species:  P.  taenoides  Rud.,  P. 
drnii<:iilatiim,  Rud.,  and  P.  vcnarum  (Treutler  1793)  Zeder  1803. 
Among  these  species,  it  is  probable  that  Treutler's  description  was  of  an 
artifact  rather  than  a  parasite,  and  tlie  other  two  have  been  i-cmoved  to 
the  Linguatulidae. 

Pohjstoma  thijnii  was  described  from  the  gills  of  Scomber  fhynnus 
by  Delaroche  (1811).  Rudolphi  (1819)  renamed  this  species  P.  dupUca- 
tum  and  added  a  new  species  P.  occllatum  from  tlie  tliroat  of  Emgs 
europa.  This  species  is  regarded  as  identical  witli  that  described  by 
Kuhl  and  Hassalt  (1822)  from  the  nasal  cavity  of  Ilalirhrli/s  atra.  P. 
logiginis  was  described  by  delle  Chiaje  (1823)  from  LoUgo  vulgar i,<. 
Blainville  (1828)  oriented  the  polystomes  correctly  and  transferred  P. 
iniegerrimum,  P.  orellatum,  and  P.  thgnii  to  a  new  genus  Ile.xacotyle, 
naming  H.  thynii  as  type.  According  to  the  rules  of  zoological  nomen- 
clature, however,  the  genus  Polystoma  must  be  retained.    Kuhn  (1829) 


10  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [290 

described  P.  appcndiciilatain  from  Squalus  catuhis.  Dujardio  (1845) 
transferred  Didibothrium  crassicaudatum  Leuck.  1835  =  Diplobothrium 
itrmatum  Leuck.  1842  to  the  genus  Polystoma,  and  listed  as  additional 
species,  P.  duplicatum,  P.  pinguicola,  P.  ocdlatum,  P.  intcgcrrimum,  and 
P.  appcndiculatum.  Diesing  (1850)  named  P.  loliginis  and  P.  appcndic- 
vlatum  as  types  of  new  genera  Solenocotyle  and  Onchocotj-le.  He  re- 
moved P.  armatum  to  the  genus  Didibothrium  Leuck.  and  retained  in 
the  genus  Polystoma  ouh'  the  species  P.  infigcrrimum  and  P.  occlkitum. 
Tlie  genus  Polystoma  together  with  the  genera  Tetrastomum,  Gry- 
])orhyneluxs,  Hexathyridium,  Notocotyle,  Aspidocotyle,  and  Aspidogas- 
ter  were  included  by  the  same  author  in  the  tribe  Polycotylea. 

In  his  revision  Diesing  (1859)  reduced  the  trematodes  to  the  rank 
of  a  tribe  and  divided  the  group  into  three  subtribes:  Acotylea,  Coty- 
lophora,  and  Plectanophora.  The  second  of  these  subtribes  he  subdi\'i- 
ded  into  three  families :  Monocotylea,  Tricotylea,  and  Polycotylea.  The 
last  of  these  corresponds  almost  identically  with  his  former  tribe  Poly- 
cotylea. He  rejected  Gryporhynchus,  and  added  the  genera  Ancyroceph- 
alus,  Plagiopeltis,  Heptastomum,  Onchocotjde,  Cyclocotyle,  and  Solen- 
ocotyle. In  the  family  Polycotylea  he  recognized  two  subfamilies: 
Aplacocotylea  with  the  suckers  set  directly  in  the  body,  and  Placocotylea 
with  the  suckers  set  in  a  median  posterior  plate.  In  the  latter  he  in- 
eluded  the  genera  Onchocotyle,  Polystoma,  Cyclocotyle,  Aspidocotyle, 
Aspidcgaster,  and  Solenocotyle. 

Then  followed  the  great  work  of  van  Beneden  (1858)  with  an  ex- 
perimental demonstration  of  the  "direct"  development  of  the  many- 
suckered  ectoparasitic  trematodes,  and  the  "indirect"  development  of 
the  distomes.  For  the.se  two  groups  he  proposed  the  names  Monogenea 
and  Digenea.  In  the  former  he  recognized  two  families:  the  Tristomi- 
dae  with  a  single  posterior  sucker,  and  the  Polystoraidae  with  several 
posterior  suckers.  In  the  Polystomidae  he  included  the  genera  Polystoma, 
Diplozoon,  Octobothrium,  Axine,  Onchocotyle,  Calceostoma,  and  Gyro- 
dactylus. 

Later  van  Beneden  and  Hesse  (1863)  made  the  genera  Octocotyle 
(  =  Octobothrium),  Udouella,  and  Gyrodactylus  types  of  new  families, 
thus  increasing  the  number  of  families  to  five.  Many  additional  genera, 
both  old  and  recently  described,  were  now  for  the  first  time  placed  with 
the  Monogenea.  But  in  the  family  Polystomidae  these  authors  retained 
only  two  genera,  Polystoma  and  Erpocotyle;  and  in  the  genus  Polystoma 
was  listed  onlj'  a  single  species,  P.  intcgerrinium. 

Taschenberg  (1879)  reverted  to  the  earlier  classification  of  van 
Beneden  and  adopted  the  division  of  the  moncgeuetic  trematodes  into  two 


291]  XORTH  AMERICAX  rOLYSTOMIDAE—STUSKARD  11 

groups  Tristomeae  and  Polystomeae,  which  he  regarded  as  families 
Under  the  Polystomeae  as  subfamilies  he  listed  Polystomidae,  Octoboth- 
ridae  (  =  Oetocotylidae),  Gyrodaetylidae,  and  the  new  subfamily  Micro- 
eotylidae ;  the  latter  including  Microcotyle,  Axiue,  Gastrocotyle  and  the 
entirely  unlike  genera,  Aspidogaster,  Cotylaspis  and  Aspidoeotyle.  To 
the  Polystomidae  he  added  the  genera  Onchocotyle  and  Diplobothriura, 
and  in  the  genus  Polystoma  included  the  two  species  P.  intcgcrriinum 
and  P.  occllaium. 

In  regard  to  the  previously  mentioned  forms  St.  Remy  (1891)  fol- 
lowed the  famih'  and  subfamily  divisions  of  Taschenberg,  tho  adding 
new  genera  to  each  of  the  subfamilies  and  removing  Aspidogaster,  Coty- 
laspis, and  Aspidoeotyle  from  the  Microcotylidae.  To  the  Polystomidae, 
Wright  and  Maeallum  had  added  the  genus  Sphyrauura,  and  in  the  genus 
Polystoma  were  listed  the  new  species  P.  oblongum  Wriglit  and  P.  coro- 
nafum  Leidj'. 

Increased  knowledge  of  the  trematodes  disclosed  so  many  exceptions 
to  their  classification  according  to  life  history  that  Monticelli  (1892) 
proposed  a  new  arrangement  of  the  group,  based  on  morphological  char- 
acters. To  contain  the  forms  previously  classed  as  Monogenea,  he  pro- 
posed the  suborder  Heterocotylea.  He  raised  the  Monocotylidae  and 
Gyrodaetylidae  from  subfamily  to  family  rank,  making  five  families  in 
the  Heterocotylea.  In  the  family  Polystomidae  he  retained  the  sub- 
families Polystominae,  Oetoeotyliuae,  and  Microeotylinae  of  former 
authors. 

So  far  as  the  Polystomidae  are  concerned,  the  synopsis  of  Pratt 
(1900)  does  not  differ  from  that  of  St.  Remy  and  Monticelli. 

Later  Monticelli  (1903)  worked  out  a  new  classification  of  the 
Heterocotylea,  separating  the  forms  on  the  basis  of  differences  in  the  ad- 
hesive apparatus.  He  an-anged  the  families  in  two  tribes,  Oligocotylea 
and  Polj'cotylea,  the  former  containing  the  forms  with  few  suckers  and 
the  latter  those  with  many  suckers.  This  division  he  says  is  not  of  great 
systematic  importance  but  may  be  of  practical  value  in  the  identiiicatiou 
of  families.  In  the  Oligocotylea  he  included  the  families  Tristomidae, 
Slonocotylidae,  Udonellidae,  Calceostomidae,  Gyrodaetylidae,  and  Dico- 
tylidae ;  and  in  the  Polycotylea  the  families  Polystomidae,  Oetocotylidae, 
Hexacotylidae,  Platycotylidae,  Pleurocotylidae,  and  Microcotylidae. 
Among  these  the  Udonellidae,  Oetocotylidae,  and  Microcotylidae  are 
raised  from  subfamily  to  family  rank,  and  the  Calceostomidae,  Dicoty- 
lidae,  Hexacotylidae,  Platycotylidae,  and  Pleurocotylidae  are  new  fam- 
ilies. The  family  Polystomidae  contained  the  single  genus  Polystoma 
with  the  species  P.  integerrhnum,  P.  occllutuin,  P.  oblongum,  P.  coro- 
natum,  and  P.  hassalli. 


12  ILUXOIS  BIOLOGICAL  MOXOGRAPHS  [292 

Diseiassing  the  classification  of  Monticelli,  Odlmer  (1912)  stated  that 
he  considered  the  number  of  suckers  of  secondary  importance  and  the 
system  based  on  them  therefore  lacking  in  fundamental  systematic  sig- 
nificance. Accordingly  he  rejected  the  work  of  Monticelli,  and  using  the 
older  classification  of  Monogenea,  divided  the  forms  within  the  group  on 
the  basis  of  differences  in  the  female  reproductive  diicts.  He  discussed 
the  relationship  of  the  ducts  of  the  female  genital  system  in  various  trema- 
tode  and  cestode  genera,  and  stated  that  he  was  convinced  as  was  claimed 
by  Stieda  that  Laurer's  canal  of  the  trematodes  should  be  regarded  as 
homologous  with  tlie  vagina  of  the  cestodes.  Intervening  authors,  Looss 
(1893),  Goto  (1894)  and  several  other  writers,  had  considered  Laurer's 
canal  of  the  Malacocotylea  as  homologous  with  the  genito-intestinal  canal 
of  certain  Ileterocotylea,  and  not  with  the  vagina  of  the  cestodes.  Odh- 
ner  argued  that  Laurer's  canal  was  the  primitive  vagina  of  the  trema- 
todes and  that  there  had  been  a  change  of  vaginal  function  from  this 
canal  to  the  teimiinal  part  of  the  uterus,  with  the  resulting  degeneration 
of  the  former  duct.  It  now  served  in  his  opinion  only  to  carry  ofi'  excess 
spermatozoa,  together  with  yolk  and  shell  substance  not  used  in  the  for- 
mation of  the  eggs.  Pie  adds  that  there  is  no  evidence  on  which  to  base 
an  explanation  of  the  transfer  of  the  seat  of  vaginal  function  from 
Laurer's  canal  to  the  terminal  part  of  tlie  uterus ;  it  must  only  be  accepted 
as  a  fact. 

According  to  Odhner,  in  the  group  of  monogenetic  trematodes,  two 
very  different  structures  are  included  under  the  term  vagina.  One  pres- 
ent in  the  Tristomidae,  Monocotylidae,  and  Gyrodaetylidae  opens  to  the 
exterior  on  the  left  side  of  the  ventral  surface,  and  at  the  inner  end  is 
enlarged  to  form  the  seminal  receptacle.  This  tube  he  considered  homo- 
logous to  the  vagina  of  the  cestodes  and  Laurer's  canal  of  the  digenetic 
trematodes.  The  other  structures  which  he  did  not  consider  homologous 
to  this  true  vagina  were  the  ducts  of  the  Octocotylidae,  Polystomidae, 
and  Microcotylidae,  which  function  as  vaginae  and  open  into  the  vitelline 
collecting  ducts.  These  are  paired  and  open  to  the  surface  either  ven- 
trally,  laterally,  or  dorsally.  Contending  that  they  had  arisen  siti  generis, 
he  proposed  for  them  the  name  "ductus  vaginalis."  Considering 
tlie  question  of  whether  the  paired  or  unj^aired  condition  of  these 
ducts  was  primitive,  he  argued  that  originally  the  duct  was 
unpaired  and  opened  ventrally;  that  the  opening  became  divided 
and  the  duct  split,  therefore  the  Y-shaped  duct  of  Kajonchocotyle 
must  be  considered  as  a  stage  in  the  development  of  the  paired  condition 
of  the  ducts.  A  further  separation  would  give  the  lateral  openings  of 
Polystoma.  In  the  Microcotylidae  the  openings  have  migrated  dorsally 
and  fused  producing  a  single  dorsal  tube.  Odhner  could  find  no  homo- 
logue  for  the  genito-intestinal  canal  and  since  he  maintained  that  it  was 


293J  XORTIl  AMEKICAX  POLYSTOMIDAE—STUXKARD  13 

not  homologous  witli  Laurer's  canal,  coiu-huled  that  it  had  arisen  sui 
generis. 

On  the  basis  of  these  differences  in  the  female  genital  duets  he 
divided  the  Mouogenca  into  two  suborders :  Monopisthocotylea  and  Poly- 
opisthoeotylea.  The  former  is  characterized  by  the  absence  of  tlie  gonito- 
intpstinal  canal,  the  presence  of  a  "true  vagina"  and  a  single  pos- 
terior organ  of  attachment;  the  latter  bj-  the  presence  of  the  genito- 
intestinal  canal,  "ductus  vaginalis,"  many  posterior  adhesive  organs, 
and  the  absence  of  a  "true  vagina."  In  the  Monopisthocotylea 
he  included  the  families  Tristomidae,  jMonocotylidae,  Udonellidae 
and  Gyrodactylidac ;  and  in  the  Polyopisthocotylea  the  families 
Polystomidae,  ]\Iicrocotylidae  and  Octoeotylidae.  He  pointed  out  that 
by  tlie  removal  of  the  genus  Sphyranura,  the  Oligocotjdea,  the  first  of 
Jlontieelli's  tribes  agrees  entirely  with  his  suborder  llonopisthocotylea. 
In  the  second  of  Mouticelli's  tribes,  however,  the  Diclidophorinae,  to- 
gether with  the  genera  Dactylocotyle  and  Hexacotyle,  should  be  re- 
moved from  the  Octoeotylidae  and  placed  with  the  Microcotylidae,  since 
the}-  more  nearly  agree  with  the  latter  forms  in  internal  structure. 

The  next  year  Odhner  (1913)  reaffirmed  his  idea  of  the  homologj' 
of  the  vagina  of  the  cestodes  and  Laurer's  canal  of  the  distomes, 
but  explained  therewith  that  his  denial  of  the  homology  of  the 
genito-intestinal  canal  and  Laurer's  canal  had  been  based  on  an  error  of 
Cerfontaine  in  describing  an  unpaired  vagina  as  present  in  the  genus  Dac- 
tylocotyle. On  examination  of  this  genus  ho  had  found  that  a  "true 
vagina"  was  absent,  and  concluded  that  tlie  "true  vagina"  of  the  Mono- 
pisthocotylea which  lie  had  homologized  with  Laurer's  canal  was  never 
j)resent  together  with  the  genito-intestinal  canal.  From  this  he  decided 
tliat  tlie  "true  vagina"  was  homologous  with  the  genito-intestinal  canal 
ami  therefoi-e  with  Laurer's  canal.  Now  maintaining  the  homology  of 
the  "true  vagina''  and  the  genito-intestinal  canal  he  is  i;i  my  opinion 
obliged  to  dismiss  the  presence  or  absence  of  the  genito-intestinal  canal 
as  a  basis  of  difference  between  his  suborders,  and  explain  why  in  one 
group  this  canal  opens  to  the  exterior  on  the  ventral  side  of  the  body 
and  in  the  other  opens  into  the  intestine.  His  homology  of  the  "true 
vagina"  and  the  genito-intestinal  canal  is  a  most  serious  error  since  it 
would  invalidate  tlic  distinguishing  feature  which  separates  the  two 
suborders. 

I  propose  to  sliow  that  the  organ  which  functions  as  a  vagina  is 
liomologous  in  all  tlie  monogenctic  trcmatodes,  and  that  there  can  be  no 
division  of  the  group  on  the  basis  of  difl^'erences  suggested  by  Odliner. 
In  fact,  the  work  of  Odhner  is  based  on  an  incorrect  assumption  and 
false  homologies.  Starting  with  the  assumption  that  Laurer's  canal  is 
homologous  to  the  vagina  of  the  cestodes,  he  has  missed  the  truth  in  his 


14  ILLIXOIS  BIOLOGICAL  MOXOGR.IPHS  [294 

entire  discussion  and  when  at  a  loss  to  explain  a  structure  has  derived  it 
sui  generis.  His  later  paper  (1913)  admitting  the  homology  of  Laurer's 
and  the  genito-intestinal  canals  corrected  one  mistaken  contention,  but 
his  separation  of  the  female  copulatory  ducts  into  a  true  vagina  and 
"eanalis  vaginalis"  seems  entirely  \vithoi;t  foundation.  There  is  no  evi- 
dence to  support  the  idea  that  the  single  vagina  is  not  homologous  to  the 
paired  vaginae.  In  fact,  Odhner  described  the  paired  vaginae  as  arising 
by  the  division  of  a  single  unpaired  tube,  probably  ventral  in  position. 
He  derived  this  tube  sui  generis,  and  cited  no  reason  why  it  is  not  homo- 
logoiis  with  the  ventral  unpaired  vagina  of  the  Monopisthocotylea.  Fur- 
ther he  gives  no  means  of  distinguishing  between  the  two. 

Looss  (1893)  presented  a  strong  argument  to  prove  that  Laurer's 
canal  is  not  a  vagina,  nor  homologous  to  the  vagina  of  the  cestodes. 

Goto  (1894)  reveiewed  the  literature  up  to  that  date  and  gave  a 
careful  and  detailed  study  of  the  eanalis  gc nito-intcstinalis.  Making  a 
very  clear  and  comprehensive  analysis  of  the  question  and  summarizing 
evidence  from  a  wide  study  of  ectoparasitic  forms,  he  concluded  that  the 
genito-intestinal  canal  and  Laurer's  canal  are  homologous  and  that 
neither  are  homologous  with  the  vagina  of  the  Monogenea.  He  showed 
that  in  the  group  there  is  a  perfect  series  of  vaginae  from  a  truly  paired 
to  a  truly  unpaired  condition.  He  discvissed  the  idea  of  Braun  who  re- 
garded the  presence  of  a  single  vagina  as  the  result  of  a  simple  atrophy 
of  one  of  the  originally  paired  vagina,  with  the  conclusion  that  the  rela- 
tions of  the  ducts  "point  strongly  to  the  view  that  the  impaired  vagina 
has  been  formed  by  the  union  and  subsequent  displacement  of  the  ori- 
ginally paired  vaginae,  and  not  as  Braun  supposes  by  the  atrophy  of  one 
of  them." 

In  the  present  study,  the  histological  character  and  the  relative  posi- 
tion and  relationships  of  the  ducts  of  the  female  system  support  the  con- 
tention of  Looss  and  Goto  that  Laurer's  canal  is  homologous  with  the 
genito-intestinal  canal,  and  affords  no  evidence  that  these  ducts  have  any 
further  homologue.  A  review  of  the  literature  and  the  study  of  the  ducts 
in  the  three  families  discussed  in  this  paper  has  convinced  me  that 
Laurer's  canal  is  homologous  to  tlie  genito-intestinal  canal  ;and  the  vagina 
of  the  Monopisthocotylea  is  homologous  with  the  originally  single,  sub- 
sequently paired,  and  secondarily  fused  vaginae  of  the  Polyopisthocotylea. 
It  makes  no  difference  whether  the  single  or  paired  condition  is  regarded 
as  primitive.  Given  a  single  unpaired  vagina  as  described  by  Odhner 
for  the  Monopisthocotylea ;  by  a  division  of  the  external  part  and  subse- 
quent lateral  migration  of  the  openings,  the  paired  vaginae  of  the  Poly- 
opisthocotylea are  explained.  These  duets  entering  the  body  from  the 
sides,  lying  parallel  with  the  vitelline  ducts  and  discharging  into  the 


295]  XORTH  AMERIC.LX  POLYSTOMIDAE—STiWKARD  15 

same  cavity,  became  fused  at  their  internal  ends  with  the  vitelline  ducts 
and  this  union  continued  outward  to  the  location  where  the  vitelline 
ducts  turn  toward  the  follicles  and  the  vaginae  branch  off  to  open  to  the 
exterior.  The  advantage  of  a  single  duet  over  two  ducts  lying  side  by 
side  is  obvious,  and  the  fusion  of  two  parallel  ducts  is  not  uncommon  in 
other  groups.  With  a  further  dorsal  migration  of  the  opening  of  the 
vaginae  there  would  be  a  separation  of  the  vitelline  and  vaginal  canals 
and  a  dorsal  fusion  of  the  vaginae  would  give  the  single  dorsal  vagina  of 
Octobothrium,  Axine,  and  Microcotyle.  The  earlier  fusion  of  the  vitel- 
line and  vaginal  canals  would  retard  the  secondary  fusion  of  the  internal 
ends  of  the  dorsal  vaginae  and  this  explains  the  single  dorsal  pore  and 
internally  paired  vagina  of  Axine  hctcroccrca  which  is  used  by  Odhner 
as  an  argument  supporting  his  idea  that  in  the  jMonogenea  two  different 
structures  are  included  under  the  term  vagina. 

I  agree  with  Odhner  that  the  seminal  receptacles  of  Sphyrauura  are 
homologous  to  the  paired  vaginae  of  Polystoma,  and  that  this  furnishes 
a  splendid  example  of  the  change  whereby  the  terminal  part  of  the  uterus 
has  assumed  the  copulatory  function.  It  may  be  that  further  specializa- 
tion in  this  direction,  due  to  the  endoparasitic  habit  and  self  fertilization, 
may  explain  the  absence  of  the  vagina  of  the  distomes. 

It  now  remains  only  to  account  for  the  absence  of  the  genito-in- 
testinal  canal  in  the  Monopisthocotylea.  Odhner  stated  that  this  struc- 
ture is  homologous  M'ith  Laurer's  canal,  and  in  his  (1912)  paper  called 
attention  to  the  fact  that  Laurer's  canal  is  a  "rudimentary  organ" 
which  serves  no  essential  function.  The  vestigeal  character  of  Laui-er"s 
canal  is  believed  in  by  most  writers — Looss,  ]\Ionticelli,  Brandes,  Goto, 
etc.  This  structure  is  entirely  lacking  in  some  distome  groups  and  in 
others  is  represented  by  a  blind  sac  opening  from  the  ootype.  Since  the 
genito-intestinal  canal  is  admittedly  homologous  to  Laurer's  canal  and 
the  latter  is  kno^vn  to  be  a  vestigeal  structure,  it  appears  reasonable  to 
suppose  that  it  has  degenerated  in  the  ^Monopisthocotylea. 

There  is  a  possibility  that  the  Monopisthocotylea  instead  of  having 
lost  a  genito-intestinal  canal  may  have  arisen  fi'om  a  group  of  the  Tur- 
bellaria  which  had  no  homologous  structure,  but  this  explanation  seems 
very  improbable.  Haswcll  (1907)  described  in  certain  Australian  poly- 
clads  a  tube  which  formerly  had  been  considered  an  accessory  or  dorsal 
vagina  but  which  in  certain  forms  opened  into  the  intestine.  The  pres- 
ence of  this  genito-intestinal  canal  in  polyclads,  he  says,  "strengthens  the 
contention,  so  ably  supported  by  Goto,  that  the  genito-intestinal  canal 
and  not  the  vagina  of  the  Heterocotylea  is  the  equivalent  of  the  Laurer's 
canal  of  the  Malacocotylea." 

The  absence  of  the  genito-intestinal  canal  in  the  ^lonopisthocotylea 


16  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [296 

is  undoubtedly  a  feature  of  distinct  taxonomic  importance,  and  the  work 
of  Odhner  is  an  advance  step  in  the  formation  of  a  natural  system  and 
the  final  classification  of  the  monogenetic  forms.  Since  the  arrangement 
of  ilouticelli,  based  on  the  character  of  the  adhesive  apparatus,  so  nearly 
agrees  with  that  of  Odhner  which  in  reality  is  based  on  the  presence  or 
absence  of  a  genito-intestinal  canal,  it  appears  that  both  these  features 
are  of  large  importance  in  the  taxonomy  of  the  group.  Present  evidence 
is  insiifificient  to  decide  which  is  of  greater  significance.  Further  study 
may  show  that  there  is  complete  agreement  in  classifications  based  on 
both  features. 

Odhner  (1912)  argued  that  the  removal  by  Monticelli  of  Sphyranura 
from  the  family  Polystomidae  on  the  basis  of  the  difference  in  number 
of  suckers  was  not  justified.  As  previously  stated,  the  writer  agrees  with 
Odhner  that  the  seminal  receptacles  of  Sphyranura  are  homologous  M'ith 
the  vaginae  of  Polystoma,  and  the  agreement  in  type  of  genital  ducts  in- 
dicates a  closer  relationship  between  these  genera  than  is  assigned  in  the 
system  of  Monticelli.  Sphyranura  undoubtedly  should  be  placed  with  the 
Polyopisthocotylea.  There  are,  however,  wide  and  fundamental  differ- 
ences between  it  and  the  genus  Polystoma,  and  while  future  researches 
may  discover  intermediate  forms  which  will  make  it  possible  to  include 
them  with  certainty  in  a  single  family,  for  the  present  such  a  grouping  is 
hardly  justified  and  the  two  families  should  be  retained,  altho  the  name 
Dieotylidae  of  Monticelli  does  not  conform  to  the  rules  of  zoological 
nomenclature. 

THE  GENUS  POLYSTOMA 

The  family  Polystomidae  as  considered  in  this  paper  contains  only 
the  genus  Polystoma.  The  members  of  this  genus  are  widely  distributed, 
species  having  been  described  from  all  the  continents  except  South 
America.  The  species  are  not  only  widely  distributed  geographically, 
but  also  vary  widely  in  type  of  host  and  in  locatisn  within  the  host. 
They  are  parasitic  in  the  urinary  bladder  of  frogs  and  toads  and  on  the 
gills  of  frog  larvae,  and  also  infest  the  urinary  bladder  and  phar3-ngeal 
cavity  of  many  species  of  turtles. 

The  structure  and  development  of  Polystoma  integerrinium  has  been 
investigated  by  Stieda  (1870),  Zeller  (1872  and  1876),  Willemoes-Suhm 
(1872),  Halkin  (1902),  Goldschmidt  (1902),  and  Andre  (1910).  Zeller 
(1876)  described  two  forms  of  P.  integerrimum,  one  which  became  ma- 
ture in  the  urinary  bladder  of  the  frog,  and  the  other  which  became  ma- 
ture on  the  gills  of  the  frog  tadpole.  These  two  forms  of  the  parasite 
show  wide  differences  in  size  and  internal  structure.  The  form  which 
becomes  mature  in  the  urinary  bladder  is  much  larger,  has  a  lobed 
testis,  external  vaginae,  and  a  long  coiled  uterus  which  contains  many 


297]  XORTH  AMERICAN  POLYSTOMIDAE—STUXKARD  17 

eggs.  The  form  maturing  on  the  gills  of  the  tadpole  has  a  spherical 
testis,  lacks  external  vaginae  and  a  long  coiled  uterus,  and  has  a  small 
uterine  cavity  in  which  a  single  egg  develops.  Ilalkin  and  Goldschmidt 
have  investigated  the  early  stages  in  this  form,  but  the  writer  has  been 
unable  to  find  any  reference  to  work  on  the  later  larval  stages.  The 
findings  of  Zeller  are  so  unusual  that  one  is  led  strongly  to  suspect  he 
confused  two  different  species. 

The  descriptions  of  P.  oceUatum  by  Rudolphi  (1819)  and  Kuhl  and 
Hassalt  (1822)  are  very  brief;  that  by  Willemoes-Suhm  (1872)  contains 
one  plate,  and  Looss  (1885)  figured  only  the  structures  at  the  distal  ends 
of  the  excretory  tubules. 

The  description  of  P.  oUongum  Wright  (1879)  contains  sufficiently 
detailed  information  for  a  specific  diagnosis  and  is  illustrated  by  three 
figures.  Stafford  (1905)  reported  P.  ohlongum  from  the  palate  of  Chry- 
semys  picta  and  the  same  location  in  Chehjdra  serpentina,  but  since 
"Wright  originally  described  the  species  from  the  urinary  bladder  of 
Aromochelys  odoratus,  Braun  reviewing  Stafford's  article  considered 
the  form  from  the  oral  cavity  as  a  different  species.  The  form  described 
by  Leidy  as  P.  oblongum,  was  reinvestigated  by  Goto  (1899)  and  proved 
to  be  a  different  species  from  that  described  by  "Wright,  but  the  material 
he  reports  was  in  such  a  poor  state  of  preservation  that  renewed  study 
was  impossible  and  so  the  form  must  remain  unknown. 

Leidy's  (1888)  description  of  P.  coronatum  is  so  bi-ief  that  it  is  al- 
most valueless ;  a  type  specimen  mounted  as  a  toto  pi'eparation  has  been 
available  for  the  present  study  and  many  additional  points  of  structure 
are  added  to  the  original  description. 

P.  Jwssalli  was  described  by  Goto  (1899)  from  the  urinary  bladder  of 
Cinosternum  pcnnsyhmnicum  and  has  been  collected  by  the  writer  from 
the  iirinary  bladder  of  Aromochelys  odoratus,  A.  carinatus,  and  Chelydra 
serpentina,  as  well  as  from  Cinosternum  pennsylvanicum.  Additional 
data  correct  and  siipplement  the  description  of  Goto. 

Johnston  (1912)  described  P.  iulliense  from  the  urinary  bladder  of 
two  species  of  Hyla  from  New  South  Wales,  Australia.  Beauchamp 
(1913)  described  P.  alluaudi  from  an  unknown  batrachian  from  the  lower 
prairies  of  Kinangop,  Africa;  the  material  was  collected  by  the  African 
expedition  of  Alluaud  and  Jeannel.  Stewart  (1914)  described  P.  kachu- 
gae  from  the  urinary  bladder  of  the  water  tortoise,  Kachuga  lineata,  at 
Lucknow,  India. 

In  the  genus  Polystoma  present  evidence  supports  the  validity  of  the 
following  described  species  listed  in  the  order  of  description : 

P.  integerrimum  Frolich  1791.  From  the  urinary  bladder  of  frogs 
and  toads  and  the  gills  of  frog  larvae ;  Europe. 


18  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [298 

P.  ocellatum  Rudolphi  1819.  From  the  throat  and  nasal  cavity  of 
Emys  europa  and  Halichelys  atra;  Europe. 

P.  ohlongum  Wright  1879.  From  the  urinary  bladder  of  Aromo- 
chclys  odoratus;  North  America. 

P.  coronatum  Leidy  1888.  From  the  fauces  of  the  terrapin ;  North 
America. 

P.  hassalli  Goto  1899.  From  the  urinary  bladder  of  Cinosternum 
pennsylvanicum,  Aromochclys  odoratus,  A.  carinatus,  and  Chelydra  ser- 
pentina; North  America. 

P.  bullicnsc  Johnston  1912.  From  the  urinary  bladder  of  Hyla 
phyllochros  and  H.  Lcsueurii;  Australia. 

P.  alluaudi,  Beauchamp  1913.  From  an  unknown  batrachian ; 
Africa. 

P.  kachugae  Stewart  1914.  From  the  urinary  bladder  of  Kachuga 
lineata;  India. 

In  the  present  work  evidence  is  submitted  to  justify  the  inclusion  of 
the  following  new  species: 

P.  orhiculare  Stunkard  1916.  From  the  urinary  bladder  of  Pseu- 
demys  scripta  and  Chrysemys  marginata;  North  America. 

P.  opacum  Stunkard  1916.  From  the  pharynx  of  Trionyx  fcrox  and 
Malacoclemmys  lesueurii;  North  America. 

P.  mcgacotyle  Stunkard  1916.  From  the  mouth  of  Chrysemys  mar- 
ginata; North  America. 

P.  microcotyle  Stunkard  1916.  From  the  mouth  of  Chrysemys  mar- 
ginata; North  America. 

With  the  exception  of  P.  integerrimum,  the  members  of  the  genus  are 
very  rarely  found  and  the  number  of  individuals  discovered  is  very  small. 
Wright  described  P.  ohlongum  from  two  specimens;  Leidy,  P.  corona- 
tum. from  four  specimens;  Johnston  had  sixteen  specimens  of  P.  iulliense; 
Beauchamp  described  P.  alluaudi  from  a  single  specimen ;  Stewart  had 
only  two  specimens  of  P.  kachugae.  The  writer  had  only  a  limited  num- 
ber of  individuals  of  any  species ;  P.  microcotyle  was  described  from  a 
single  specimen;  P.  orbicidare  from  nine  specimens;  P.  opacum  and  P. 
megacotyle  each  from  three  specimens.  Becavise  of  the  limited  amount 
of  material,  it  has  been  impossible  to  attempt  special  technique  to  differ- 
entiate the  various  organ  systems,  and  the  descriptions  are  therefore  in- 
complete in  certain  particulars.  The  general  morphological  features  are 
however  described  in  sufficient  detail  that  clear  specific  diagnoses  can  be 
made,  and  in  certain  instances  the  finer  structure  and  histology  of  the 
organs  has  been  described. 


299]  XORTH  AMERICAX  POLYSTOMID.IE—STUXKARD  19 

ANATOMY    AND   HISTOLOGY    OF   THE    POLYSTOMIDAE 

The  species  that  have  been  included  in  the  genus  Polystoma  show  a 
much  wider  range  of  structural  variation  than  is  usually  present  in  a 
natural  genus.  There  are  wide  differences  in  the  character  of  digestive 
and  reproductive  systems,  and  variation  exists  in  the  type  of  adhesive 
apparatus. 

There  is  wide  variation  in  size;  P.  intrgcrrimum,  the  largest  known 
species  measures  up  to  12  mm.  in  length,  and  P.  hassalli  is  only  1.3  to  2 
mm.  in  length.  The  width  is  one-third  to  one-fifth  of  the  total  length. 
All  the  worms  that  have  been  included  in  this  genus  have  a  flattened, 
elongate  oval  body  which  at  the  posterior  end  bears  a  large  ventral 
muscular  disc  or  cotylophore.  The  body  is  more  or  less  pointed  at  the 
anterior  end  and  at  the  posterior  end  may  or  may  not  have  a  con.striction 
just  before  the  attachment  of  the  caudal  disc.  As  in  all  trematodes  the 
shape  is  subject  to  considerable  variation  as  the  animal  elongates  and 
contracts.  Locomotion  is  accomplished  by  attaching  the  anterior  sucker 
and  then  bringing  the  caudal  disc  forward ;  as  a  result  of  the  terminal 
attachments  and  the  "looping"  method  of  progression,  the  dorsal  line  of 
the  body  is  more  or  less  arched  and  the  ventral  surface  is  concave.  In 
certain  species  at  the  openings  of  the  vaginae  on  the  lateral  or  ventro- 
lateral margins  of  the  body,  there  are  prominent  swellings,  the  ''Seiten- 
wiilste " "  of  Zeller.  These  structures  are  not  present  in  any  of  the  known 
North  American  species. 

Organs  of  Attachment. — The  caudal  disc  bears  on  its  ventral  face 
the  chief  organs  of  attachment.  These  consist  of  suckers  and  hooks,  the 
former  arranged  in  pairs,  three  suckers  on  each  side  of  the  median  line. 
The  two  posterior  suckers  are  close  together  and  those  of  the  middle  pair 
are  separated  by  a  considerable  distance,  while  the  anterior  pair  may  or 
may  not  be  near  each  other.  In  all  previously  reported  forms  except  P. 
alliiaudi,  the  anterior  suckers  are  separated  by  a  considerable  distance, 
giving  the  disc  the  shape  described  b}'  Leidy  as  cordiform  (Fig.  27).  In 
the  single  specimen  of  P.  alluaudi  described  by  Beauchamp,  both  the 
caudual  and  cephalic  suckers  are  separated,  while  those  of  each  side  are 
contiguous.  In  P.  orbiculare  the  anterior  suckers  are  in  the  same  close 
proximity  as  the  caudal  pair,  and  each  sucker  of  the  disc  is  separated 
from  the  two  adjacent  to  it  by  uniform  distances,  making  a  perfect  circle 
of  suckers  (Fig.  1).  In  the  six  species  described  by  the  writer  these 
suckers  are  complicated  structures,  set  more  or  less  deeply  in  the  paren- 
chyma of  the  caudal  disc.  Their  structure,  character  of  insertion,  mus- 
cular attachments,  and  relation  to  the  surrounding  tissue  indicate  that 
they  are  protrusible  and  retractile,  and  in  fact  such  movements  may  be 
observed  bv  watching  the  live  worm. 


20  ILLIXOIS  BIOLOGICAL  MOXOGRAPIIS  [300 

The  suckers  are  cup  shaped  (Fig.  34),  and  in  all  the  species  describ- 
ed in  this  paper  are  constructed  on  an  elaborate  cutieular  framework. 
According  to  Zeller  the  sucker  forms  as  a  ridge  around  a  larval  hooklet 
and  later  sinks  into  the  parenchyma,  and  this  method  of  origin  explains 
the  cutieular  covering  of  the  external  and  internal  surfaces  of  the  cup. 
Riuming  across  between  these  cutieular  membranes,  tliere  ai'e  short  re- 
fractive fibers  which  constitute  the  mass  of  tlie  wall  of  the  sucker  (Fig. 
35).  Wright  and  Macallum  (1887)  describing  similar  fibers  in  the  walls 
of  the  suckers  of  Sphyranura  say,  "Instead  of  the  substance  of  the 
sucker  being  formed  of  muscular  fibers  disposed  in  three  directions,  and 
capable  of  modifying  the  shape  of  the  cavity,  as  in  the  distomes,  it  is  not 
possessed  of  contractility  in  Sphyranura  (and  probably  in  Polystoma), 
and  is  formed  of  prismatic  Abel's,  rather  of  a  supportive  than  a  muscidar 
character,  arranged  perpendicularly  between  the  concave  and  convex 
limiting  membranes  of  the  suckers."  Goto  (1894)  described  similar 
fibers  in  the  suckers  of  Axine,  Microcotyle,  Oetocotyle,  Diclidophora, 
Hexacotyle,  and  Onchocotyle  and  considered  them  to  be  more  of  an  elastic 
than  a  contractile  nature.  They  are,  he  states,  difi'erent  from  the  ordi- 
nary muscular  fibers  of  the  body  and  from  those  of  the  suckers  of  the 
Tristomidae  and  Monocotylidae,  as  well  as  from  those  of  the  anterior 
sucker  of  Onchocotyle,  both  in  optical  characters  and  in  reaction  toward 
staining  fluids.  The  structure  of  the  suckers  in  these  forms  and  their 
mode  of  operation  are  discussed  by  Goto  at  considerable  length,  but  as  the 
suckers  he  described  are  constructed  on  a  different  type  of  cutieular 
framework  from  that  present  in  the  genus  Polystoma,  obviously  the  type 
of  suctorial  action  is  different. 

In  all  the  species  described  in  this  paper,  the  fibers  which  form  the 
walls  of  the  posterior  suckers  are  similar  to  those  described  by  Wright 
and  Macallum  and  Goto;  the  cutieular  framework  is  also  flexible  and 
elastic,  but  is  of  a  different  type  from  that  described  by  Goto.  In  the 
polystomes  investigated  by  the  writer,  with  the  exception  of  P.  integer- 
rimum,  the  sucker  consists  of  three  sections  or  zones  which  may  be  desig- 
nated as  basal,  intermediate,  and  external  or  distal  (Fig.  36).  The  ex- 
ternal part  or  rim  of  the  sucker  is  supported  by  numerous  cutieular  rods 
formed  by  the  thickening  at  regular  intervals  of  the  cutieular  lining. 
These  rods  are  bent  outward,  their  curvature  maintaining  the  flare  of  the 
rim  of  the  sucker.  Distally  thej^  terminate  just  inside  the  rim  of  the  cup 
and  basally  they  are  continuous  with  and  are  processes  from  a  band  of 
cuticula  which  passes  around  the  sucker  and  separates  the  external  and 
intermediate  portions.  In  toto  preparations  this  band  appeal's  to  be 
divided  into  sections  that  are  almost  square,  each  with  a  circular  area  in 
the  center  that  increases  and  decreases  in  size  as  the  focus  is  changed. 


3011  XORTH  AMERICAX  POLYSTOMIDAE—STUSKARD  21 

Sections  show  that  the  cuticular  lining  of  the  sucker  is  folded  outward 
against  the  convex  wall  with  which  it  is  fused,  thus  interrupting  the  con- 
tinuity of  the  fibrous  wall  (Fig.  35).  The  two  sides  of  this  invagiuated 
cuticular  sac  or  ring  are  fused  at  regular  intervals,  leaving  small  pockets 
alternating  with  the  places  of  fusion.  These  small  openings  in  the  cuti- 
cular band  are  conspicuous  by  reason  of  their  different  refractive  index 
and  show  very  plainly  with  a  dark  field  illumination  as  the  square  or 
rectangular  sections  with  the  circular  areas  in  the  center  (Fig.  3i). 
There  is  apparently  no  relation  between  the  number  of  these  sections  in 
the  cuticular  band  and  the  number  of  cuticular  thickenings  which  serve 
as  supports  of  the  external  section. 

The  middle  section  of  the  sucker  extends  basally  from  the  previously 
described  cuticular  band  to  a  somewhat  similar  evagination  of  the  cuti- 
cular lining  into  the  wall  of  the  sucker,  but  this  evagination  does  not  ex- 
tend to  the  external  cuticular  covering  of  the  sucker  and  onlj-  partially 
divides  the  fibrous  wall.  This  middle  or  intermediate  portion  of  the 
sucker  is  supported  by  thickenings  of  the  cuticular  lining,  processes  that 
extend  peripherally  from  the  cuticular  band  which  passes  around  the 
sucker  at  its  base.  These  supporting  ridges  are  not  arranged  at  regular 
intervals  and  they  are  much  fewer  in  number  than  the  cuticular  rods 
which  support  the  external  section.  They  are  often  branched,  tho  not 
more  than  a  single  bifurcation  was  observed. 

The  basal  portion  of  the  sucker  is  circular,  similar  in  structure  to  the 
portions  previously  described  ;  it  has  internal  and  external  limiting  mem- 
branes with  fibers  extending  between.  At  its  center  the  cuticular  and 
fibrous  wall  is  interrupted  and  there  is  the  structure  described  by  John- 
son (1912)  as  the  connective  tissue  plug,  which  appears  as  a  central  disc 
or  button,  and  to  which  the  retractor  muscles  are  attached.  This  central 
disc  has  thickened  cuticular  edges  and  bears  the  larval  booklet.  Figure 
44  illustrates  the  method  of  operation  of  the  suckers.  Muscles  are  at- 
tached to  the  external  wall  of  the  distal  and  intermediate  portions  of  the 
sucker  and  the  contraction  of  these  muscles  retracts  the  two  external 
zones,  with  the  accompanying  protrusion  of  the  basal  part.  Whether  the 
small  hooks  at  the  bases  of  the  suckers  are  functional  is  doubtful.  As 
previously  described,  the  cuticular  supports  do  not  extend  quite  to  the 
external  margin  of  the  sucker,  leaving  a  soft  plastic  edge  which  can  be 
applied  all  the  waj-  around  even  on  an  irregular  surface.  With  the  con- 
traction of  the  muscles  attached  to  the  basal  disc,  a  vacuum  is  produced 
and  forms  a  powerful  means  of  adhesion.  Since  the  walls  of  the  sucker 
are  not  contractile  and  the  suckers  vary  only  slightlj'  in  size  in  a  single 
species,  the  size  of  the  suckers  has  been  used  by  the  writer  as  a  character 
for  determining  specific  identity. 


22  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [302 

A  cuticular  framework  similar  to  that  present  in  Polystoma  was 
described  by  Wright  and  Macallum  for  the  suckers  of  Sphi/ranura  osleri. 
They  say:  "As  the  wall  of  the  sucker  is  itself  destitute  of  contractility, 
another  arrangement  exists  for  modifying  the  shape  of  the  cavity.  Its 
walls  is  really  divided  into  three  concentric  zones,  which  by  special  ex- 
trinsic muscles  can  be  worked  independently.  The  two  circular  lines 
which  separate  these  zones,  are  marked  by  an  infolding  of  the  investing 
membrane,  which  forms  a  sort  of  joint,  permitting  an  independent  move- 
ment of  the  zones." 

The  collection  of  Professor  Ward  contains  a  single  series  of  sections 
of  P.  intcgcrrimvm  from  Germany,  and  in  this  specimen  the  type  of 
skeletal  structure  just  described  is  absent.  Figure  45  shows  the  charac- 
ter of  the  suckers  in  this  form.  The  caudal  disc  typically  bears  eighteen 
hooks.  Sixteen  are  similar  in  size  and  shape,  arranged  as  follows :  six 
in  a  row  between  the  anterior  suckei's,  one  situated  inside  each  sucker 
at  the  base,  and  four  between  the  two  posterior  suckers.  In  addition  to 
these  hooks  there  is  a  pair  of  great  hooks,  several  times  the  size  of  the 
small  hooks,  between  the  two  posterior  suckers.  The  shape  of  these  hooks 
and  their  arrangement  are  shown  in  Figures  37  to  43.  In  many  cases 
there  is  only  one  pair  of  the  small  hooks  between  the  caudal  suckers ;  in 
such  eases  in  addition  to  the  great  hooks  there  is  a  third  pair,  similar  in 
shape  to  the  great  hooks  and  intermediate  in  size  between  the  great  and 
small  hooks. 

The  sixteen  small  hooks  are  present  on  the  caiulal  disc  of  the  larva 
before  the  suckers  are  formed  and  are  called  larval  booklets  by  Wille- 
moes-Suhm  (1872),  but  Zeller  (1876)  says:  "Die  sechszehn  kleinen 
Hakchen  mit  iliren  Oesen,  welche  die  Haftseheibe  angehoren  und  welche 
bei  der  Polystomum  larva  so  ausscrordentlich  deutlich  zu  erkennen  ist, 
sind  nieht,  wie  Willemoes-Suhm  meint,  nur  'Larvalorgane'.  Sie  werdeu 
nicht  abgeworfen,  sondern  sind  wie  ich  auf  das  bestimmeste  wiederholen 
muss,  bei  der  erwachsenen  Thiere  noch  sammtlieh  vorhanden,  sehr 
beweglich  und  gewiss  nicht  ohne  Bedeutung  fiir  ein  festeres  Anheften." 
Jolinston  (1912)  in  the  description  of  P.  huUicnsc  says:  "Four  larval 
booklets  are  present  in  a  row-  on  the  ventral  surface  near  the  posterior 
edge  of  the  disc  or  cotylophore.  I  have  been  able  to  find  no  trace  either 
in  the  living  worms  or  the  fixed  material,  of  the  larval  booklets  which 
P.  intcgerrimum  and  other  species  bear  near  the  anterior  edge  of  the 
disc.  There  is  a  small  anchor  shaped  hook  in  the  base  of  each  sucker. 
All  these  hooks  either  disappear  as  the  animal  increases  with  age,  or  very 
readily  become  detached.  In  only  one  out  of  sixteen  specimens  have  the 
whole  four  posterior  booklets  been  present ;  and  in  only  two  others  were 
any  booklets  at  all  to  be  seen.  In  all  other  specimens  no  liooklets  could 
be  made  out." 


303]  XORTH  AM  ERIC  AX  POLYSTOMIDAE—STUXKARD  23 

In  my  own  material  I  find  that  the  larval  hooklets  are  invariably 
present  in  the  bases  of  the  suckers,  but  of  the  other  larval  hooklets,  us- 
ually several  are  absent  and  often  those  present  are  so  arranged  that  it  is 
difficult  to  see  how  they  could  function  in  attachment.  Those  at  the  an- 
terior edge  of  the  caudal  disc  are  seldom  regularly  arranged,  and  in 
many  eases  (Figs.  37  to  43)  are  in  such  irregular  and  unusual  positions 
with  reference  to  each  other  that  the  use  of  one  would  interfere  with  the 
action  of  the  others. 

The  great  hooks  are  invariably  present  in  the  species  in  which  the 
caudal  disc  is  cordiform  in  shape,  i.  e.,  where  the  two  anterior  suckers  are 
separated  by  a  distance  exceeding  that  between  the  two  posterior  suckers. 
In  the  species  P.  alliunidi  and  P.  orbiculare  the  disc  is  circular  and  the 
great  hooks  are  absent.  Usually  the  cordiform  disc  is  wider  and  the  cir- 
cular disc  is  narrower  tlian  the  body.  At  first  it  seemed  possible  to 
separate  the  genus  into  two  subgenera,  one  in  which  the  disc  is  circular 
and  the  great  hooks  are  absent  and  another  with  a  cordiform  disc  and 
great  hooks  present,  but  there  seems  to  be  no  such  clear  line  of  separation. 
In  P.  orbiculare  a  large  number  of  chitinous  spicules  are  present  on  the 
disc,  some  between  the  suckers  and  the  others  in  the  central  area  of  the 
disc.  In  P.  opacum  the  disc  is  intermediate  in  shape ;  it  is  difficult  to 
determine  whether  it  is  circular  or  cordiform,  and  the  great  hooks  are 
present  altho  they  are  not  more  than  half  the  size  of  those  in  other  species 
(Fig.  40).  In  P.  hassalli  the  disc  at  times  may  be  circular  and  the  great 
hooks  are  strongly  developed  (Fig.  31). 

Bodij  Covering. — The  body  is  covered  with  a  non-cellular,  unarmed 
cuticula,  which  is  turned  in  at  the  external  openings  of  the  various  sys- 
tems. It  does  not  have  a  uniform  appearance  but  is  traversed  by  lines 
which  extend  perpendicular  to  the  surface  of  the  body. 

Musculature. — The  musculature  consists  of  the  dernio-muscular  sac, 
the  muscles  of  the  adhesive  apparatus,  and  dorso-veutral  strands  with 
much-branched  fibers  wliieh  traverse  the  body  at  irregular  intervals.  The 
muscles  of  the  body  wall  consist  of  an  external  circular  layer,  an  interme- 
diate layer  of  diagonal  fibers,  and  inside  the  latter,  bundles  of  longitud- 
inal fibers.  In  all  the  species  studied,  the  inner  longitvidinal  fibers  are 
more  strongly  developed  than  either  of  the  other  layers.  Stieda  (1870) 
in  P.  intcgcrrimum  did  not  distinguish  between  the  two  external  muscle 
layers  and  described  only  two  layers  of  muscles,  an  outer  layer  of  an- 
nular fibers,  some  of  which  were  not  exactly  circular  and  crossed  each 
otlier,  and  an  inner  layer  of  longitudinal  fibers.  Zeller  (1876)  was  in 
error  when  he  described  the  diagonal  fibers  as  inside  the  longitudinal 
layer  in  P.  integerrimum.  The  arrangement  of  the  muscles  of  the  body 
wall  in  Polystoma  is  the  usual  condition  in  the  Heteroeotylea,  and  a 


24  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [304 

similar  arrangement  has  been  described  in  Calicotyle,  Axine,  Nitzscliia. 
Tristomum,  Octobothrium,  Temnocephala,  Microeotyle.  Octocotyle,  and 
Monocotyle.  In  Diclidophora  Goto  (1894)  described  an  additional  layer 
of  longitudinal  fibers  between  the  circular  and  diagonal  layers.  He  states 
that  in  Onchocotyle  and  Hesaeotyle  the  circular  fibers  seem  to  be  en- 
tirely lacking.  In  the  genus  Polystoma  there  are  strong  sets  of  longitudinal 
fibers  near  the  median  line  on  the  ventral  side  of  the  body.  They  could 
be  traced  antei'iad  only  to  the  testis.  Posteriad  they  pass  into  the  caudal 
disc  and  together  with  fibers  from  the  body  wall  are  inserted  on  the  sides 
and  in  the  bases  of  the  bothria.  Muscle  strands  from  both  sides  of  the 
body  pass  to  each  of  the  suckers  (Fig.  29)  and  smaller  groups  of  fibers 
from  each  sucker  to  each  of  the  others.  In  addition  to  the  dorso-ventral 
muscles  which  extend  between  various  points  of  the  body  wall,  there  are 
other  fibers  from  the  body  wall  to  the  internal  organs. 

Mcscnchyma. — The  mesenchymal  tissue  of  the  body  does  not  show 
a  differentiation  into  ectoparenehyma  and  endoparenchyma  as  described 
by  Brandes  (1892)  and  other  writers;  it  is  not  of  a  uniform  character, 
but  presents  differences  in  appearance  at  different  points  in  the  same 
specimen.  It  may  take  the  form  of  compact  cellular  tissue,  or  of  vacuo- 
lated cells,  or  there  may  be  large  vacuoles  apparently  between  cells,  or 
the  cellular  sti-ucture  may  be  entirely  lacking,  there  being  only  a  reticu- 
lum of  fibrous  tissue.  The  parenchyma  is  traversed  by  many  muscle 
strands,  and  the  dorsal  and  lateral  regions  are  occupied  by  the  enormous- 
ly developed  vitellaria  (Figs.  19,  23). 

Alimentary  System.— The  digestive  apparatus  consists  of  a  terminal 
anterior  or  oral  sucker,  a  pharynx,  a  short  esophagus  and  a  bifurcate  in- 
testine. The  oral  sucker  (Fig.  6)  is  not  fully  homologous  with  that  of 
the  distomes.  There  is  no  external  limiting  membrane,  branched  muscle 
fibers  passing  from  the  inside  lining  of  the  sucker  to  the  body  wall. 
Posteriorly  it  is  limited  and  separated  from  the  body  parenchyma  by 
special  strands  of  fibei-s  which  pass  from  the  body  wall  to  the  Mall  of  the 
digestive  tube  and  are  attached  there  just  anterior  to  the  pharynx.  A 
contraction  of  these  fibers  causes  the  constriction  between  the  anterior 
sucker  and  the  body  parenchyma  which  is  sometimes  seen.  Longitudinal 
muscle  fibers  from  the  body  parenchyma  penetrate  this  posterior  boun- 
dry  of  the  anterior  sucker  and  pass  to  the  wall  of  the  sucker.  Annular 
muscles,  situated  just  inside  the  cutic\ilar  lining,  pass  around  the  sucker 
from  side  to  side.  Situated  among  the  muscle  fibers  there  are  large 
secretory  cells.  Johnston  described  the  structure  as  a  weakly  developed 
or  incipient  oraj  sucker.  The  anterior  sucker,  pharynx,  and  esophagus 
are  lined  with  cuticula  continuous  with  that  of  the  external  surface  of 
the  body. 


305]  NORTH  AMERICAN  POLYSTOMIDAE—STUNKARD  25 

The  pharynx  is  approximately  spherical,  altho  various  states  of  con- 
traction influence  its  shape  to  some  extent.  It  does  not  lie  directly  in  the 
long  axis  of  the  body  but  obliquely,  tlie  lumen  extending  from  the  some- 
what ventral  anterior  opening  from  the  oral  sucker  to  a  more  dorsal  pos- 
terior opening  into  the  esophagus  or  intestine.  In  certain  species  it  is 
composed  of  two  portions,  (Figs.  6,  33)  tho  both  are  enclosed  in  the  same 
external  capsule.  In  the  anterior  portion  there  are  many  strong  annular 
fibers  and  this  part  probably  acts  as  a  spliineter.  altho  there  are  also 
radial  fibers  which  extend  from  the  external  limiting  membrane  to  the 
cuticula  of  the  lumen.  In  the  posterior  part  the  annular  fibers  are  con- 
fined almost  entirely  to  the  external  region  and  a  small  central  zone 
(Fig.  25).  The  muscle  fibers  are  branched  and  non-nucleated.  Scattered 
among  the  fibers  in  the  posterior  part  there  are  large  nuclei,  each  with  a 
deeply  staining  nucleolus  and  surrounded  by  a  granular  or  flaky  area 
that  is  continued  by  a  fine  duct  traceable  by  the  presence  of  the  same 
granular  substance  and  leading  to  the  lumen  of  the  pharynx.  Goto 
described  somewhat  similar  nuclei  in  the  pharynx  of  Diclidophora  and 
regards  them  as  remnants  of  the  cells  that  have  produced  the  muscle 
fibers.  The  writer  is  inclined  to  the  view  that  in  Polystoraa  the  granular 
substance  is  a  secretion.  No  extra-esophageal  glands  were  observed,  but 
that  the  secretion  of  the  pharyngeal  cells  is  salivary  was  not  demon- 
strated. 

A  short  esophagus  may  be  present  in  certain  species  (Fig.  6)  but  in 
most  cases  the  pharynx  appears  to  open  directly  into  the  intestine  at  the 
juncture  of  the  right  and  left  ceca.  There  may  be  a  short  median  or 
paired  lateral  pockets  of  the  intestine  extending  anteriad  from  the  junc- 
tion of  the  ceca. 

There  is  wide  variation  in  the  type  of  the  intestinal  diverticula.  In 
P.  iniegcrrimum  the  ceca  are  much  branched  and  the.se  branches  ramify 
thru  the  body  and  the  caudal  disc  (Fig.  45).  In  P.  alluaudi  the  ceca  oc- 
cupy the  same  location  but  are  merely  lobed  and  have  no  secondary 
branches,  tho  they  are  united  posteriorly.  In  P.  buUiense,  according  to 
Johnston,  "a  diverticulum  from  the  buccal  cavity  i-iuis  backwards,  ven- 
tral to  the  pharynx,  and  for  a  distance  equal  to  its  length  forming  a  me- 
dian unpaired  buccal  pocket."  In  all  other  known  species  there  is  a 
simple  bifurcate  intestine,  the  ceca  terminating  just  anterior  to  the  caudal 
disc.  In  two  specimens  of  P.  hassalli,  however,  the  ceca  are  connected 
posteriorly;  in  one  of  them  tlie  ends  of  the  ceca  are  continuous  and  in 
the  other  there  is  a  connection  some  distance  anterior  to  the  ends  of  tlie 
ceca  (Fig.  30).  The  walls  of  the  diverticula  are  composed  of  a  delicate 
fibro-membranous  tissue  upon  M-hich  rests  the  digestive  epithelium.  Tlie 
einthelial  layer  consists  of  columnar  cells  whose  nuclei  lie  near  the  fibro- 


26  JLLIXOIS  BIOLOGICAL  MOXOGRAPHS  [306 

membranous  sheet  and  which  have  large,  rounded,  often  vacuolated  bodies 
extending:  irregularly  into  the  canal.  The  protoplasm  of  the  cells  is 
granular. 

Excretory  System. — In  this  family  as  in  all  Heterocotylea,  there  are 
two  excretory  pores,  situated  on  tlie  dorsal  surface  about  midway  between 
the  median  line  of  the  body  and  the  lateral  edge  of  the  worm,  near  the 
level  of  the  caudal  margin  of  the  pharynx  (Fig.  27,  33).  These  open 
from  vesicular  expansions,  which  when  filled  are  almost  spherical  and 
when  empty  have  folded  walls.  The  descending  collecting  duct  originates 
in  the  region  of  the  pharynx  from  the  fusion  of  smaller  ducts  and  passes 
posteriad  to  the  region  of  the  caudal  disc  where  it  turns  eephalad  and 
continues  as  the  ascending  collecting  duct  to  open  into  the  excretory 
vesicle.  Both  the  descending  and  ascending  ducts  receive  smaller 
branches  at  irregular  intervals;  at  the  caudal  end  of  the  body  a  canal 
joins  the  tubes  of  the  two  sides  and  a  similar  connection  exists  between 
the  descending  ducts  just  anterior  to  the  pharynx.  From  this  anterior 
communicating  canal  a  branch  enters  the  anterior  sucker  near  the  median 
line.  The  excretory  vesicles  are  lined  with  a  thin  layer  of  cuticula  con- 
tinuous with  that  of  the  external  surface  of  the  body  and  the  collecting 
ducts  and  accessory  branches  have  a  fibro-membranous  wall  in  which 
nuclei  are  occasionally  embedded.  In  P.  intcgcrrimum,  Zeller  described 
many  connections  of  the  collecting  ducts  of  the  two  sides  thru  anastomoes 
of  their  smaller  branches.  He  also  described  cilia  on  the  walls  of  the  col- 
lecting ducts.  Looss  (1885)  described  the  excretory  system  of  P.  ocella- 
turn.  He  says  the  collecting  ducts  are  not  ciliated  throuout,  but  only  in 
occasional  areas,  and  describes  cilia  in  the  capillaries.  These  capillaries 
are  long  and  at  the  distal  end  are  verj'  much  coiled.  In  this  coiled  part 
the  capillary  is  divided  so  that  two  flame  cells  discharge  into  each  coil 
and  are  emptied  by  a  single  capillary.  The  caliber  of  the  excretory  ves- 
sels is  very  minute,  and  altho  varying  somewhat  as  a  result  of  distention, 
lacunar  expansions  were  not  observed.  Because  of  the  limited  amount  of 
material,  much  of  which  was  received  in  a  preserved  condition,  no  at- 
tempt was  made  to  trace  the  excretory  system  in  living  worms  of  this 
family.  The  vitellaria  completely  obscure  the  excretory  ducts  in  toto 
preparations.  The  secondary  ducts  are  so  small  and  so  often  collapsed 
that  it  is  impossible  to  follow  their  continuity  with  certainty  in  sections. 

Nervous  System. — The  morphology  of  the  nervous  system  of  P. 
integerrimum  was  described  in  detail  by  Andre  (1910).  He  described  a 
supra-esophageal  brain  from  -which  three  pairs  of  nerves  pass  anteriad 
and  three  pairs  posteriad.  In  another  paper  (1910a)  he  gave  a  detailed 
description  of  the  eyes  of  P.  integerrimum.  In  the  present  work  no 
special  study  of  the  nervous  system  was  made  and  no  new  facts  were 
adduced. 


307]  XORTH  AMERICAN  POLYSTOMIDAE—STUNKARD  27 

Male  Reproductive  System. — The  testis  is  a  much  branched  structure 
in  P.  kachugac;  in  P.  integerrimuni  it  is  lobed,  and  in  the  other  known 
species  it  is  oval  or  spherical.  It  is  situated  near  or  slightly  anterior  to 
the  middle  of  the  body.  A  duct  designated  an  internal  vas  deferens  was 
described  in  P.  integerrimuni  by  Zeller,  but  Ijima  (1884)  traced  tlie  true 
relations  of  this  tube  and  showed  that  it  passes  from  the  ootype  to  the  in- 
testine. Goto  (1894)  proposed  the  name  canalis  gcnito-intcstinalis  for 
this  structure  which  is  discussed  in  a  later  section.  The  vas  deferens 
arises  from  the  dorso-cephalic  margin  of  the  testis  and  passes  dorsad  and 
anteriad.  It  extends  dorsal  to  the  ootype,  between  the  dorsal  margins  of 
the  ovary  and  uterus  to  the  level  of  the  genital  pore  where  it  turns  ven- 
trad  and  enlarges  to  form  the  seminal  vesicle  (Fig.  13).  From  the  semi- 
nal vesicle  a  duct  pas.ses  thru  the  cirrus  sac,  opening  into  the  genital 
atrium  (Fig.  26).  The  vas  deferens  is  small  and  has  a  tibro-membran- 
ous  wall,  and  the  seminal  vesicle  has  a  lining  of  columnar  epithelium. 
The  cirrus  sac  is  composed  of  an  external  mviscular  wall  enclosing  a  mass 
of  parenchymous  tissue  which  surrounds  the  ejaculatoiy  duct.  This  sac 
is  very  small  in  P.  intcgerrimiim  and  P.  hassalli.  Ventrally  it  opens  into 
a  common  genital  atrium  (Fig.  26).  The  ejaculatory  duct  terminates  in 
the  genital  papilla,  which  when  retracted  is  surrounded  by  a  deep  depres- 
sion. In  the  musculature  between  this  depression  and  the  wall  of  the 
cirrus  sac  are  embedded  the  roots  of  the  genital  hooks.  When  the  hooks 
are  retracted  there  is  a  shallow  depression  between  them  and  the  wall  of 
the  sac.  With  the  contraction  of  the  wall  of  the  cirrus  sac  the  genital 
papilla  and  the  circle  of  genital  hooks  are  extruded  thru  the  pore.  In 
most  of  the  species  the  hooks  are  sickle  shaped  with  the  points  project- 
ing outward,  and  with  muscles  attached  to  the  outside  of  the  hook  at  the 
juncture  of  the  root  and  shank.  These  muscles  undoubtedly  serve  as  a 
fulcrum,  and  the  extrusion  of  the  papilla  rolls  the  hooks  outward  bury- 
ing their  points  in  the  cuticula  lining  the  wall  of  the  vagina  of  the  copu- 
lating worm  (Fig.  24).  In  P.  alluaudi  Beauchamp  described  three 
genital  hooks,  P.  integerrimum  has  eight,  and  other  species  sixteen, 
thirty-two,  and  forty.  In  P.  hassalli  the  genital  hooks  are  small,  straight 
and  have  a  wing  like  process  at  the  middle. 

Zeller  described  a  prostate  gland  in  P.  integerrimum,  consisting  of 
masses  of  large  cells  situated  around  the  cirrus,  and  traced  ducts  from 
these  cells  to  the  lumen  of  the  ejaculatory  duct.  Johnston  in  P.  bulliense 
says,  "Two  laterally  placed,  small  groups  of  gland  cells  represent  the 
prostate."  The  statement  of  Zeller  that  a  gland  is  present  aroiuid  the 
cirrus  of  P.  integerrimum  is  certainly  correct.  In  the  species  described 
in  this  paper,  a  similar  gland  is  present  in  the  parenchyma  around  the 
genital  sinus.    The  cells  (Fig.  12)  are  globular  or  pyriform,  stain  deeply 


28  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [308 

and  possess  a  distinct  nucleus  and  nucleolus.  Their  ducts  could  not  be 
traced  to  the  ejaculatory  duct  but  in  many  cases  appear  to  lead  to  the 
body  wall  near  the  margin  of  the  genital  sinus.  In  P.  orbiculare,  P. 
opacum  and  P.  megacotyle  the  cirrus  sac  is  large  and  many  nuclei  are 
present  around  the  ejaculatory  duct  in  the  dorsal  part  of  the  sac.  These 
nuclei  are  large,  with  distinct  nucleoli,  and  are  surrounded  by  a  deeply 
staining  area  of  granular  or  flaky  substance,  but  no  cell  boundries  could 
be  made  out. 

Female  Reproductive  System. — In  all  known  species  but  one,  the 
ovary  is  oval  or  comma  shaped.  In  P.  kachugae  it  is  described  by  Stew- 
art as  a  "curved  sausage-shaped  organ,  the  curve  forming  all  but  a  com- 
plete circle.  The  fundus  is  somewhat  bulbous."  This  structure  is 
usually  not  more  than  one  half  the  size  of  the  testis,  is  situated  a  short 
distance  anterior  to  that  organ,  and  in  a  given  species  may  lie  on  either 
side  of  the  body.  In  all  the  species  studied  by  the  writer  it  is  comma 
shaped,  the  larger  part  is  ventral,  anterior,  and  lateral,  and  terminal 
region  is  dorsal,  posterior,  and  mesal.  The  ova  are  formed  in  the  large 
part  and  the  ovary  is  divided  into  zones  of  growth,  ova  of  increasing  size 
being  present  in  each  succeeding  zone  (Fig.  23). 

In  the  species  described  in  this  paper  the  vitellaria  consist  of  masses 
of  follicles  occupying  the  dorsal  and  lateral  regions  of  the  body.  Each 
follicle  consists  of  several  cells  which  may  vary  much  in  appearance ;  the 
difference  is  due  to  the  phase  of  secretory  activity  of  the  cells.  In  the 
peripheral  part  of  the  gland  the  cells  are  usually  small,  with  granular  or 
flaky  protoplasm,  a  distinct  nucleus  and  nucleolus;  whereas  those  more 
centrally  located  may  be  two  or  three  times  their  size,  the  extra-nuclear 
area  being  either  vacuolated  or  filled  with  droplets  of  a  yellow  substance 
(Figs.  19,  20).  In  some  cells  the  secretory  droplets  are  scattered  uni- 
formly thruout  the  cell.  The  presence  of  the  material  in  the  cells  often 
renders  the  body  so  opaque  that  the  diverticula  can  not  be  seen.  The 
glandular  secretion  is  apparently  identical  with  that  which  forms  tlie  shell 
of  the  egg,  and  this  observation  further  confirms  the  statement  of  Gold- 
schmidt  (1909)  that  the  so-called  vitellaria  secrete  the  shell  of  the  egg. 
Small  ducts  from  the  follicles  (Fig.  11)  unite  and  discharge  into  longi- 
tudinal collecting  ducts.  These  extend  along  the  sides  of  the  body,  later- 
al to  the  ceca  and  dorsal  to  the  excretory  tubules ;  on  either  side  of  the 
body  there  is  an  anterior  and  a  posterior  branch  which  unite  just  behind 
the  level  of  the  ovary  and  the  common  duct  discharges  into  the  external 
end  of  the  vitello- vaginal  canal.  In  P.  hiilliense,  Johnston  reports:  "The 
lateral  vaginal  swellings  are  formed  by  a  large  number  of  pajDillae,  per- 
forated by  fine  canals,  which  after  a  very  short  course,  open  into  a  fairly 
wide  sperm  reservoir,  situated  one  on  either  side,  just  under  the  swell- 


309]  XORTH  AMERICAS  POLYSTOMIDAESTUNKARD  29 

iiigs.  From  these  reservoirs,  a  wide  vaginal  tube  on  either  side  runs 
backwards  and  inwards,  to  open  into  the  anterior  lateral  yolk  duct." 
A  similar  condition  is  described  and  figured  by  Zeller  for  P.  intcgerri- 
mum.  In  all  other  species  in  which  the  structure  has  been  described,  the 
vaginae  are  open  funnels  leading  mediad  and  dorsad  from  their  openings 
on  the  ventro-lateral  surface  of  the  body,  and  uniting  just  below  the  in- 
testine with  the  common  vitelline  ducts  to  form  the  viteUo-vaginal  canals. 
The  cuticular  lining  of  the  vaginae  is  very  thick  and  in  the  parenchyma 
around  the  vaginae  there  are  large  cells  of  secretory  type  (Fig.  24).  The 
^^tello-vaginal  canals  lead  medially  and  unite,  either  forming  a  duct 
which  discharges  into  the  ootj-pe  (Fig.  32)  or  opening  separately  into 
the  ootype  (Figs.  3,  16,  24). 

From  the  ovary  the  o\aduct  passes  posteriad  and  ventrad,  opening 
into  the  ootype.  Immediately  anterior  and  dorsal  to  the  opening  of  the 
o^-iduet,  there  branches  from  the  ootj'pe  a  small  tube  which  after  a  some- 
what twisted  double  loop  opens  into  the  intestine  of  the  side  in  which  the 
ovarj-  is  situated.  This  genito-intestinal  canal  has  been  the  source  of 
much  controversy  and  its  presence  or  absence  is  the  diagnostic  feature  of 
Odhner's  two  groups  of  monogenetic  trematodes.  Mehlis'  gland,  the  shell 
gland  of  earlier  authors,  is  never  largely  developed  and  is  difficult  to 
find  in  some  specimens  where  it  is  represented  by  a  few  nuclei  in  the 
parenchyma  around  the  ootype.  Zeller  for  P.  integerrimum  and  John- 
ston for  P.  huUiense  described  prominent  "shell  glands",  and  Stewart 
for  P.  kachugae  described  "a  group  of  glandular  cells  found  at  the  same 
transverse  level  as  the  ovary,  but  on  the  opposite  side  of  the  midline. 
They  appear  to  be  connected  with  the  corresponding  vagina,  but  their 
function  is  obscure."  Since  they  are  in  the  precise  location  of  the 
Mehlis'  gland,  one  is  led  to  suspect  that  Stewart  was  confused  in  regard 
to  tlie  connections  and  relations  of  this  group  of  cells,  altho  in  in- 
dividuals of  other  species  studied  by  the  writer,  there  are  groups  of 
large  glandular  cells  in  the  parenchyma  surrounding  each  vagina. 

The  ootype  is  continued  by  a  tube  which  passes  anteriad  on  the  op- 
posite side  from  the  ovary,  and  which  leads  to  the  uterus.  Previous 
writers  have  called  this  tube  the  oviduct  and  Johnston  (1912)  says, 
"From  the  ootype,  the  oviduct  runs  forward  to  a  point  in  front  of  the 
ovary,  whence  it  bends  sharply  backwards  and  runs  in  a  straight  course 
close  to  the  ventral  surface,  almost  to  the  level  of  the  cotjdophore,  where 
it  opens  into  the  wide  uterus. ' '  The  use  of  the  term  o^'iduct  for  the  tube 
leading  from  the  ootype  to  the  uterus  is  confusing  and  objectionable. 
Looss  (1899)  says,  "Der  Theil  des  weiblichen  Leitungswegen,  der  den 
Keimstock  mit  deui  ootj-p  verbindet,  ist  der  oviduct  oder  Keimgang," 
and  this  terminologj'  is  found  in  general  use  thruout  the  literature.  In  a 
large  number  of  trematode  genera  the  ootype  opens  directly  into  the 


30  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [310 

Uterus.  In  the  Polystomidae  however,  there  is  a  definite  specialized  tube 
leading  from  the  ootype  to  the  uterus.  This  duet  is  not  homologous  with 
the  oviduct,  it  is  separated  from  that  duct  by  the  ootype,  and  further, 
in  the  specimens  examined  by  the  writer  the  histological  character  of  the 
two  are  not  precisely  the  same.  The  epithelial  lining  of  the  oviduct  is  of 
the  flattened  type,  and  that  of  the  second  duct  more  columnar.  Such  a 
duct  is  present  in  many  cestode  genera  and  is  called  the  uterine  duct. 
The  same  name  is  proposed  for  the  tube  leading  from  the  ootype  to  the 
uterus  in  the  Polystomidae,  altho  with  the  understanding  that  its  use  is 
independent  of  the  question  of  homologies  of  the  female  ducts  in  treraa- 
todes  and  cestodes. 

In  P.  hulliensc  the  uterine  duct  opens  into  the  uterus  not  at  the  end 
but  on  the  side,  and  there  is  a  posterior  uterine  pocket.  The  uterus  ex- 
tends as  a  wide  elongated  sac  from  the  extreme  posterior  end  of  the  body 
to  the  common  genital  sinus.  In  P.  alluaudi  the  intracecal  area  is  occu- 
pied by  the  uterus  and  eggs  are  present  almost  as  far  posteriad  as  the 
caudal  union  of  the  ceca.  In  P.  integerrimum  there  is  a  long  icterus 
which  extends  in  many  loops  anterior  to  the  ootype,  and  contains  a  large 
number  of  eggs.  In  all  other  kno\^^l  forms,  the  uterus  is  situated  at  the 
level  of  the  ovary  on  the  opposite  side  of  the  body,  and  contains  a  single 
large  egg  or  embryo.  Zeller  (1876)  described  a  similar  condition  for 
the  ectoparasitic  form  of  P.  integerrimvm.  Figure  14  shows  a  very  early 
embyro  of  P.  orbicidarc  and  Figure  23  a  much  later  stage  of  development 
in  P.  megacotyle.  No  shell  is  present  in  the  former  case,  altho  it  may 
have  been  lost  in  sectioning.  There  must  be  some  provision  for  the 
growth  of  the  embryo  and  the  shell  can  not  be  rigid  during  the  uterine 
period.  Where  the  oviduct  arises  from  the  ovary,  at  its  union  with  the 
ootype,  and  at  either  end  of  the  uterine  expansion  sphincter  muscles  pro- 
duce short  contracted  portions  of  the  tube.  In  all  the  species  studied  by 
the  writer,  with  the  exception  of  the  vitelline  tubules,  all  ducts  of  the 
female  system  have  a  fibro-membranous  wall  and  an  epithelial  lining, 
which  in  the  ootype,  uterine  duct,  and  uterus  consists  of  tall  columnar 
cells  with  distinct  boundries  and  single  nuclei.  Describing  tlie  ei^ithelial 
cells  lining  the  ootype  in  certain  other  mouogenetie  forms  Goto  (1894) 
says  that  because  of  their  appearance  and  reaction  to  stains  he  strongly 
suspects  theii'  glandular  nature,  but  since  a  shell  gland  is  present  he  can 
not  understand  their  function.  In  certain  species  of  Polystoma  Mehlis' 
gland  is  much  reduced  or  absent,  and  in  these  forms  the  cells  of  the 
epithelial  lining  of  the  ootype  appear  to  be  secretive  (Figs.  8,  9).  This 
agrees  with  the  present  conception  that  the  vitellaria  secrete  the  shell 
substance  and  Mehlis'  gland  the  fluid  in  which  the  eggs  are  suspended. 

The  genital  pore  is  situated  on  the  ventral  surface  in  the  median 


311]  XORTH  AMERICAN  POLYSTOMIDAE—STUXKARD  31 

line,  just  posterior  to  the  bifurcation  of  the  digestive  tract.  It  opens 
from  a  common  genital  sinus  (Figs.  13,  26)  into  which  the  uterus  dis- 
charges and  thru  which  the  cirrus  is  extruded.  The  opening  from  the 
uterus  into  the  genital  sinus  is  posterior  and  ventral,  while  the  cirrus  sac 
opens  into  the  dorsal  part  of  the  atrium. 

When  the  two  specimens  of  P.  opacum  from  Trionyx  ferox  were 
placed  in  a  watch  glass,  they  soon  came  in  contact  and  immediately 
started  copulation,  the  cirrus  of  each  worm  was  inserted  in  the  right 
vagina  of  the  other,  and  the  two  worms  attached  to  each  other,  both  with 
the  anterior  suckers  and  those  of  the  caudal  disc  that  coidd  be  brought  in 
position  for  adhesion.  Attempts  to  separate  the  worms  failed,  so  an 
effort  was  made  to  fix  them  in  the  copulating  condition,  but  they  separated 
on  the  application  of  the  killing  flvud.  This  explains  the  statement  of 
Johnston :  ' '  On  one  side  only,  in  the  specimens  sectioned,  was  the 
vaginal  tube  filled  with  sperms;  that  on  the  other  side  was  empty." 
Benham  (1901)  and  Mac  Galium  (1913)  state  that  copulation  in  poly- 
stomes  has  been  observed  only  by  Zeller. 

POLYSTOaiA  ORBICULAKE  Stunkard  1916 
[Figures  1  to  14] 

The  material  of  this  species  consists  of  six  specimens  from  the 
urinary  bladder  of  Pseudemys  scripta  from  Raleigh,  North  Carolina, 
one  specimen  from  the  urinary  bladder  of  Chrysemys  marginata  from 
Chicago,  Illinois,  and  two  specimens  from  the  urinary  bladder  of  Chry- 
semys marginata  from  Creston,  Iowa. 

The  body  is  an  elongate  oval,  slightly  more  pointed  anteriorly  than 
posteriorly,  and  in  two  of  the  specimens  with  slight  indentations  of  the 
body  walls  at  the  vaginae  and  at  the  posterior  margin  of  the  anterior 
sucker.  These  worms  (Fig.  1)  varied  in  length  from  2.7  to  3.75  mm. 
and  in  width  from  0.9  to  1.2  mm.  The  caudal  disc  is  circular,  0.8  to 
1.07  mm.  in  width,  and  bears  the  six  suckers  arranged  symmetrically 
in  a  circle.  The  suckers  are  approximately  0.3  mm.  in  diameter,  and 
are  separated  by  regular  equal  intervals.  No  hooks  could  be  found  on 
the  caudal  disc  with  the  exception  of  the  single  minute  larval  booklet 
in  the  base  of  each  sucker.  These  are  0.016  mm.  in  length  and  could  be 
seen  only  under  favorable  conditions. 

The  anterior  sucker  (Fig.  6)  is  0.25  to  0.27  mm.  in  length  and 
0.37  to  0.42  mm.  in  width.  It  opens  into  the  pharynx,  a  spherical  struc- 
ture 0.24  to  0.28  mm.  in  diameter.  There  is  a  short  esophagus  visible 
in  sagittal  sections  altho  it  is  not  distinguishable  in  toto  preparations. 
The  ceca  meet  anteriorly  in  a  wide  curve  and  extend  as  simple  tubes 


32  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [312 

almost  to  the  posterior  end  of  the  body.  They  have  no  branches  and 
terminate  blindly.     In  caliber  they  vary  from  0.04  to  0.116  mm. 

The  testis  is  spherical  or  oval,  visually  slightly  longer  than  broad, 
and  measures  0.29  to  0.39  mm.  in  width  and  0.36  to  0.5  mm.  in  length. 
It  is  near  or  slightly  anterior  to  the  middle  of  the  body.  The  sperm 
duet  arises  at  its  anterior  margin  and,  lying  dorsal  to  the  ootype,  passes 
anteriad.  In  front  of  the  ovary  it  turns  ventrad  and  expands  into  the 
seminal  vesicle.  At  the  outer  end  of  the  seminal  vesicle  the  duct  is 
encircled  by  a  sphincter  muscle,  and  then  known  as  the  ejaculatory 
duct  passes  thru  the  cirrus  sac  to  open  into  the  genital  atrium  (Figs. 
3,  13).  The  cirrus  sac  is  almost  spherical,  and  consists  of  an  external 
muscular  capsule  filled  with  parenchjonatous  tissue  enclosing  a  central 
canal.  In  the  dorsal  part  of  the  sac  there  are  radial  muscles  passing 
from  the  wall  to  the  central  duct,  and  among  these  fibers  a  few  large 
nuclei.  More  ventrally  there  are  sets  of  muscles  developed  around  the 
central  duct  and  these  are  connected  to  the  wall  of  the  sac.  Externally 
the  central  canal  terminates  at  the  apex  of  a  papilla  which  is  separated 
by  a  deep  depression  from  the  muscivlar  ring  that  bears  the  hooks  of 
the  genital  coronet.  This  conical  muscular  ring  is  protrusible  and  is 
separated  from  the  wall  of  the  cirrus  sac  by  a  second  depression.  The 
invaginations  on  either  side  of  the  genital  coronet  allow  for  the  extru- 
sion of  the  coronet  of  hooks  with  the  genital  papilla  on  the  contraction 
of  the  wall  of  the  cirrus  sac,  while  the  muscles  attached  to  the  central 
canal  and  the  muscular  ring  bearing  the  genital  hooks  serve  as  retract- 
ors. The  genital  coronet  consists  of  sixteen  hooks,  similar  in  size  and 
shape ;  they  have  an  external  sickle-shaped  part  or  shank  which  turns 
outward  and  a  root  or  basal  part  of  about  the  same  length  embedded 
in  the  musculature  (Figs.  2,  13).  The  basal  part  is  straight  and  hollow 
and  the  internal  end  is  bifurcate.  It  bears  many  fine  cuticular  processes 
which  are  particularly  prominent  near  its  union  with  the  shank.  In  the 
body  parenchyma  around  the  terminal  part  of  the  cirrus  sac  there  are 
large  iiuicellular  glands  (Figs.  12,  13). 

The  ovary  is  lateral  and  may  be  situated  on  either  side  of  the  body. 
It  is  0.1  to  0.25  mm.  anterior  to  the  testis.  It  is  ovoid  in  shape,  with 
the  larger  part  in  which  the  ova  are  being  formed  anterior  and  ventral, 
and  the  oviduct  arising  from  the  dorsal  posterior  region.  In  sections  it 
appears  to  be  marked  into  zones,  with  larger  and  fewer  cells  present  in 
each  succeeding  zone.  It  is  0.1  to  0.148  mm.  in  width,  0.14  to  0.185  mm. 
in  length  and  in  one  specimen  cut  in  cross  sections  0.175  mm.  in  depth. 
The  oviduct  arises  as  a  very  small  tube  and  immediately  expands  (Fig. 
3).  This  expanded  portion  extends  posteriad  and  ventrad  and  by  means 
of  a  short  constricted  tube  opens  into  the  ootype,  a  specialized  region 


313]  XORTH  AMERICAN  POLVSTOMIDAE—STLWKARD  33 

of  the  female  duet  where  the  vitello-vagiual  canals  are  received  and  the 
geuito-intestinal  canal  is  given  off.  The  genito-intestinal  canal  twists 
in  a  double  loop  and  then  opens  into  the  intestine  of  the  side  upon 
which  the  ovary  is  located  (Fig.  10).  The  vaginae  are  ventro-lateral  in 
position  and  open  to  the  exterior  by  funnel  shaped  mouths.  The  vitel- 
laria  occupy  the  dorsal  and  lateral  regions  of  the  body;  they  extend 
anteriad  to  the  pharynx  and  posteriad  to  the  caudal  disc.  There  is  a 
strand  of  follicles  across  the  dorsal  side  of  the  body  just  behind  the 
pharynx,  and  then  the  follicles  are  entirely  extracecal  in  the  field  ante- 
rior to  the  testis;  posterior  to  the  testis  the  vitellaria  overlie  the  eeca 
and  extend  to  the  center  altho  they  are  scanty  along  the  median  line. 
Ventrally  the  vitellaria  are  entirely  extracecal.  Collecting  ducts  run 
longitudinally,  laterad  of  the  ceca ;  and  just  below  the  cecum  of  either 
side  the  common  vitelline  ducts  formed  by  the  union  of  the  anterior 
and  posterior  longitudinal  ducts  unite  with  the  internal  ends  of  the 
vaginae  to  form  the  vitello-vaginal  canals.  These  canals  open  directly 
into  the  ootype,  one  on  either  side,  and  are  thus  continuous,  forming  a 
canal  thru  the  body  from  side  to  side.  Mehlis'  gland  is  represented  by 
i.iany  nuclei  which  lie  in  the  parenchyma  around  the  ootype  and  uterine 
duct.  This  latter  duct  passes  anteriad  and  laterad  on  the  opposite  side 
from  the  ovary ;  it  is  smaller  than  the  ootype  in  diameter  and  the  epithe- 
lial lining  is  lower.  After  a  slight  expansion  it  is  constricted  and  then 
opens  into  the  uterus.  The  uterus  contained  a  single  egg  or  embryo. 
Figure  14  shows  a  morula-like  mass  of  cells  found  in  one  specimen ;  in 
the  other  specimens  there  were  large  spherical  eggs,  each  enclosed  in  a 
yellow  shell.    They  vary  from  0.21  to  0.24  mm.  in  diameter. 

The  excretory  system  shows  no  departure  from  the  typical  form 
and  while  it  can  not  be  completely  followed  in  sections,  the  larger  ducts 
occupy  the  characteristic  positions.  The  descending  collecting  duets 
arise  in  the  region  of  the  anterior  sucker  and  pass  posteriad,  lying  lat- 
eral and  ventral  to  the  ceca.  They  wind  back  and  forth  in  short  curves 
and  at  the  posterior  end  of  the  body  turn  anteriad  and  pass  in  the  same 
winding  course  to  the  excretory  vesicles.  Both  descending  and  ascend- 
ing ducts  receive  small  branches  at  irregidar  intervals.  The  excretory 
pores  are  lateral  and  dorsal,  at  the  level  of  the  bifurcation  of  the 
intestine  (Fig.  7). 

This  species  agrees  with  P.  alluaudi  in  shape  of  caudal  disc  and 
absence  of  great  hooks,  but  differs  from  that  species  in  type  of  uterus, 
number  of  hooks  in  tlie  genital  coronet,  and  in  the  character  of  the 
intestinal  diverticula  and  testis.  P.  oriiculare  agrees  with  P.  hassalli 
in  the  number  of  genital  hooks,  but  the  hooks  are  different  in  size  and 
shape ;  P.  hassaUi  lias  the  great  hooks  of  the  caudal  disc  well  developed 


34  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [314 

whereas  they  are  absent  in  this  species.  In  certain  particulars  P.  or- 
hicidarc  resembles  P.  opacum,  but  the  two  species  have  different  num- 
bers of  hooks  in  the  genital  coronets ;  they  differ  also  in  the  relative  size 
of  caudal  suckers.  The  great  hooks  of  the  caudal  disc  are  present  in 
P.  opacum.  The  two  species  differ  also  in  that  one  is  parasitic  in  the 
urinary  bladder  and  the  other  in  the  oral  cavity. 

POLYSTOMA  OPACUM  Stunkard  1916 
[Figures  15  to  21] 

Two  worms  of  this  species  were  obtained  from  the  esophagus  of  a 
single  specimen  of  Trionyx  ferox  from  Newton,  Texas,  and  another 
from  the  esophagus  of  Malacoclcmmys  lesueurii  from  the  same  region. 
These  trematodes  were  the  same  color  as  the  lining  of  the  esophagus 
and  so  firmly  attached  that  they  were  removed  only  with  great  difficulty. 

The  worms  (Fig.  15)  measured  4,  3.75,  and  3.25  mm.  in  length  and 
1,  0.85  and  0.8  mm.  respectively  in  width.  The  body  has  an  elongate 
oval  outline,  is  flattened  dorso-ventrall.y,  and  observed  in  living  condi- 
tion, shows  great  variations  in  shape.  In  an  extended  condition  it  nar- 
rows at  either  or  both  ends,  and  the  contracted  form  may  be  not  more 
than  half  the  length  when  extended,  and  broadly  oval  or  quadrate  in 
outline.  The  caudal  disc  is  slightly  wider  than  the  body  in  the  mounted 
specimens,  measuring  1.09  and  1.21  mm.  in  width  while  each  sucker  is 
approximately  0.4  mm.  in  diameter.  The  suckers  have  a  chitinous  skele- 
tal framework,  as  is  described  in  the  generic  discussion.  In  the  external 
meridinal  band  there  are  thirty-two  divisions,  which  number  corre- 
sponds to  the  number  of  hooks  in  the  genital  coronet.  The  suckers  are 
arranged  in  a  circle,  altho  the  anterior  pair  are  separated  by  a  distance 
slightly  exceeding  that  between  the  posterior  pair.  Between  the 
anterior  suckers  there  are  many  chitinous  spicules,  and  in  one  specimen 
two  of  the  larval  booklets.  Chitinous  spicules  are  present  on  the  sides 
of  all  the  suckers  and  over  the  ventral  surface  of  the  disc.  Between  the 
posterior  suckers  there  are  three  pairs  of  hooks,  viz.  two  pairs  of  the 
small  larval  hooks  and  one  larger  pair,  but  the  great  hooks  are  relatively 
much  smaller  than  the  corresponding  hooks  in  other  species  in  which 
they  are  present  (Fig.  40).  The  larval  booklets  are  7  to  9/*  in  length 
and  the  great  hooks  are  75;u,  in  length.  The  chitinous  spicules  present 
on  the  disc  have  no  definite  arrangement  and  their  points  may  stand 
in  any  direction ;  the  three  larval  hooks  between  the  anterior  suckers 
of  one  specimen  have  no  definite  relative  position  and  their  hooks  point 
in  different  directions;  those  at  the  posterior  edge  of  the  disc  are  set 


315]  NORTH  AMERICAN  POLYSTOMIDAESTVNKARD  3S 

in  a  row  at  more  or  less  regular  intervals  and  their  hooks  all  point 
backward. 

The  cuticular  covering  of  the  body  is  about  14ju  in  thickness,  and 
on  the  contraction  of  the  body  is  thrown  into  minute  folds  and  furrows. 

The  anterior  sucker  is  oval,  0.2  to  0.22  mm.  in  length  and  0.23  mm. 
in  width.  It  opens  into  the  pharynx  (Fig.  18),  a  spherical  structure 
.  0.3  mm.  in  width.  There  is  a  broad  nerve  commissure  crossing  the  an- 
terior part  of  the  pharynx  M'hich  contains  large  ganglion  cells.  Prom 
this  dorsal  commissure  a  nerve  passes  venti'ad  on  either  side  of  the 
pharynx. 

Tlie  digestive  tract  is  of  the  simple  triclad  type,  the  pharynx  is  fol- 
lowed by  a  short  esophagus,  0.17  mm.  in  length  in  the  sectioned  worm, 
and  the  diverticula  extend  as  simple  tubes  almost  to  the  posterior  end 
of  the  body.  They  are  about  0.15  mm.  in  diameter  and  terminate  blindly, 
dorsal  to  the  middle  pair  of  suckers  (Fig.  21).  The  eeca  are  lateral  but 
close  together,  separated  by  only  0.2  to  0.25  mm.  They  have  the  usual 
fibro-membranous  coat  and  epithelial  lining,  and  were  empty  in  the 
sectioned  individual. 

The  testis  is  spherical  or  slightly  longer  than  broad  in  well  extended 
specimens.  It  is  slightly  anterior  to  the  middle  of  the  body  and  is  com- 
posed of  a  large  number  of  lobes  or  strands  of  cells,  compacted  and 
enclosed  in  a  membranous  capsule.  Cells  with  the  chromatin  of  their 
nuclei  in  all  stages  of  division  and  mature  spermatozoa  were  observed 
in  sections.  The  sperm  duct  arises  at  the  anterior  dorsal  margin  of  the 
testis  and  curves  dorsad  and  eephalad.  Anterior  to  the  uterus  it  turns 
ventrad  and  expands  to  form  the  seminal  vesicle.  From  the  seminal 
vesicle  a  small  ejaculatory  duet  leads  through  the  cirrus  sac  and  opens 
into  the  common  genital  sinus. 

The  ovary  is  ovoid  or  comma  shaped,  situated  a  short  distance 
anterior  to  the  testis,  and  in  all  three  specimens  is  located  on  the  left 
side  of  the  body;  but  since  in  other  species  it  may  lie  on  either  side,  it 
is  probable  that  the  examination  of  a  larger  number  of  individuals 
would  show  specimens  with  the  ovary  on  the  right  side.  In  dorsal  view 
it  is  from  0.16  to  0.2  mm.  in  length  and  0.08  to  0.12  mm.  in  width,  while 
in  the  specimen  that  was  sectioned  it  is  0.08  mm.  in  widtli  and  0.3  mm. 
in  depth.  The  oviduct  arises  at  the  dorsal  posterior  margin  and  curves 
posteriad,  mediad,  and  ventrad  where  it  opens  into  the  ootype.  The 
vitello-vaginal  canals  open  separately  into  the  ootype,  just  ventral  to  the 
origin  of  the  genito-intestinal  canal.  The  latter  duct  passes  latcrad, 
then  dorsad  and  anteriad,  turns  mediad  almost  to  the  median  line  of 
the  body,  then  dorsad  and  laterad,  and  opens  into  the  intestine  of  the 
side  in  which  the  ovary  is  located.    The  uterine  duct  passes  to  the  right 


36  ILLISOIS  BIOLOGICAL  MOXOCRAPHS  [316 

sight  of  the  bodj-,  then  dorsad  and  anteriad  where  it  opens  into  the 
uterus.  Mehlis'  gland  is  present  altho  not  well  developed,  and  the  cells 
are  scattered  along  the  uterine  duct  as  well  as  around  the  ootype,  altho 
they  are  not  so  numerous  in  the  former  as  in  the  latter  location.  The 
vaginae  open  to  the  surface  on  either  side  at  the  ventro-lateral  margins 
of  the  body,  at  the  level  of  the  posterior  margin  of  the  ovary  (Fig.  16). 
On  either  side  the  inner  ends  of  the  vaginae  iinite  just  below  the  ceca 
with  the  common  ducts  from  the  vitellaria  to  form  the  vitello-vaginal 
canals.  These  open  separately  and  directly  into  the  ootype.  The  vitel- 
laria consist  of  large  compact  follicles,  underlying  the  entire  dorsal 
surface  of  the  body  from  the  pharynx  to  the  caudal  disc,  except  the 
region  over  the  ovary.  The  vitellaria  are  reduced  and  only  a  few  folli- 
cles are  present  in  the  region  over  the  testis  and  they  are  entirely  absent 
in  a  circular  area  over  the  ovary.  Ventrally  the  vitellaria  do  not  extend 
mediad  of  the  ceca.  The  vitellaria  are  so  extensively  developed  that  they 
obscure  the  internal  structures  and  render  the  body  opaque,  and  this 
character  suggested  the  name  of  the  species.  Common  collecting  ducts 
run  longitudinally  along  the  body  lateral  to  the  intestinal  diverticula 
and  these  discharge  into  the  vitello-vaginal  canals  as  previously  de- 
scribed. In  each  of  the  specimens  there  is  a  single  large  egg  in  the 
uterus,  and  in  the  one  sectioned  the  uterus  extends  eephalad  of  the 
genital  pore  and  to  a  point  0.03  mm.  from  the  bifurcation  of  the  intes- 
tine. The  eggs  are  broadly  oval,  0.25  mm.  long  by  0.2  mm.  wide.  The 
shell  is  yellow,  refractive  to  light,  and  apparentl.y  composed  of  the  same 
substance  that  occurs  in  small  droplets  in  the  vitellaria. 

The  uterus  and  cirrus  sac  open  into  the  genital  sinus;  the  opening 
of  the  cirrus  is  anterior  and  dorsal  to  that  of  the  uterus.  The  common 
genital  pore  is  situated  in  the  median  line,  about  0.12  mm.  caudad  of 
the  bifurcation  of  the  intestine.  Embedded  in  the  wall  of  the  cirrus  sac 
and  with  their  points  forming  the  so-called  coronet,  the  genital  hooks 
in  appearance  suggest  the  corolla  of  a  flower.  There  are  thirty-three 
of  these  hooks  in  one  mounted  specimen  and  thirty-two  in  the  other.  In 
entire  length  they  measure  0.05  mm.,  the  shank  or  projecting  part  com- 
prising about  half  the  total  length. 

P.  opacum  agrees  with  P.  alluaudi  and  P.  orhkulare  in  shape  of 
caudal  disc,  but  P.  alluaudi  has  but  three  spines  in  the  genital  coronet, 
and  a  long  post-ovarian  uterus  which  contains  many  eggs.  P.  orhkulare 
has  a  larger  anterior  sucker,  smaller  caudal  suckers,  a  smaller  pharynx, 
fewer  vitelline  follicles,  and  only  half  as  many  hooks  in  the  genital 
coronet.  P.  opacum  differs  from  P.  coronatum  and  P.  microcoiyle  in 
the  shape  of  the  caudal  disc  and  in  the  reduced  condition  of  the  great 
hooks  of  the  disc. 


317]  XORTH  AMERICAX  POLYSTOMIDAE—STUXKARD  37 

POLYSTOMA    MEGACOTYLE  Stunkaid  1916 
[Figures  22  to  26] 

The  material  of  tliis  species  consists  of  three  specimens  from  the 
mouth  of  Chrysemys  nmrginata  from  Crestou,  Iowa.  One  worm  was 
cut  into  cross  sections  and  the  other  two  mounted  as  stained  toto 
preparations. 

These  worms  (Fig.  22)  have  an  elongate  ovoid  shape.  Widest  in 
the  region  just  anterior  to  the  caudal  disc,  they  gradually  become  nar- 
rower anteriorly,  and  posteriorly  they  taper  rapidly  to  a  caudal  tip 
which  is  set  in  the  antero-eentral  part  of  the  caudal  disc.  The  worms 
are  2.5  to  2.7  mm.  long  and  0.71  to  0.78  mm.  in  width.  The  caudal  disc 
is  eordiform  and  the  suckers  are  so  large  that  they  slightly  overlap  each 
other.  The  suckers  are  arranged  in  about  four-fifths  of  a  circle  around 
the  lateral  and  caudal  margins  of  the  disc.  Measurements  thru  the  disc 
from  side  to  side  at  the  level  of  the  cephalic  suckers  are  from  1  to  1.4 
mm.,  thru  the  middle  pair  1.2  to  1.8  mm.,  and  thru  the  caudal  suckers 
0.68  to  0.7  mm.  The  disc  bears  the  characteristic  armature  of  liooks. 
Across  the  anterior  margin  there  are  three  larval  booklets  in  one  speci- 
men and  four  in  the  other,  but  their  arrangement  is  not  regular  or 
definite  and  their  position  would  indicate  that  tliey  do  not  function  in 
attachment.  In  the  specimen  reproduced  in  Figure  22  the  two  hooks 
of  the  right  side  have  their  points  almost  together  and  their  bases  apart. 
In  the  bases  of  the  suckers  there  are  small  larval  booklets,  and  one  pair 
similar  in  size  and  shape  between  the  two  caudal  suckers.  Also  between 
the  posterior  suckers  (Fig.  41)  there  is  the  pair  of  great  hooks  and  a 
pair  of  hooks  the  same  shape  as  the  great  hooks  and  intermediate  in  size 
between  the  great  and  larval  hooks.  The  hooks  measure  in  length :  lar- 
val 0.017  mm.,  great  hooks  0.116  mm.,  and  the  pair  intermediate  in  size 
0.058  ram. 

The  cuticular  covering  of  the  body  is  approximately  5/^  in  thick- 
ness on  the  dorsal  and  3  to  ^jj.  in  thickness  on  the  ventral  surface.  It 
is  turned  in  at  the  external  openings  and  lines  the  digestive  tract  to  the 
bifurcation. 

The  anterior  sucker  is  set  off  from  the  remainder  of  the  body  by 
a  slight  constriction.  It  is  oval,  its  longest  axis  crosswise  of  the  body, 
somewhat  flattened  posteriorly,  and  measures  0.28  mm.  in  length  by 
0.35  to  0.42  nun.  in  width.  It  is  followed  by  the  pharynx  (Fig.  25) 
which  is  0.35  to  0.38  mm.  long,  0.38  to  0.44  mm.  broad,  and  in  the  .sec- 
tioned worm  0.34  tliick.  No  esophagus  was  observed;  the  ceca  meet 
anteriorly  in  a  wide  curve  and  extend  almost  to  the  posterior  end  of  the 
body.    They  are  0.06  to  0.11  mm.  in  diameter,  and  have  an  epithelial 


38  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [318 

lining  0.017  to  0.035  mm.  in  thickness  set  upon  a  fibro-membranous  base. 
The  vitellaria  are  so  thick  that  the  diverticula  can  not  be  traced  in  toto 
preparations. 

The  testis  is  situated  near  the  center  of  the  body;  it  is  spherical 
or  oval,  0.28  to  0.33  mm.  long,  0.33  to  0.38  mm.  wide,  and  in  the  sec- 
tioned worm  0.28  mm.  thick.  The  course  of  the  vas  deferens  and  the 
character  of  the  male  organs  are  similar  to  those  in  the  previously 
described  species.  The  genital  coronet  contains  thirty-six  hooks  in  one 
and  fortj-^-two  in  the  other  toto  preparation.  They  are  similar  in  size 
and  shape,  have  a  straight  basal  portion  with  bifid  end  which  is  embedded 
in  the  wall  of  the  cirrus  sac,  and  a  sickle  shaped  shank  which  projects 
into  the  genital  atrium.  The  basal  portion  is  the  same  length  as  the 
shank  and  each  part  measures  0.03  mm. 

The  ovary  (Fig.  23)  is  a  broad  comma-shaped  organ,  situated  about 
midway  between  the  pharynx  and  testis,  on  either  side  of  the  body. 
The  larger  part  is  anterior  and  ventral  and  contains  many  nuclei  of 
forming  ova,  and  there  are  zones  of  developing  ova,  each  with  larger 
and  fewer  cells  until  dorsally  and  posteriorly  the  oviduct  is  given  off. 
The  oviduct  passes  mediad,  expanding  slightly,  and  then  posteriad  and 
ventrad  to  open  into  the  ootype.  This  structure  is  in  the  ventral  part 
of  the  body,  just  anterior  to  the  testis  (Fig.  24)  ;  from  the  sides  it  re- 
ceives the  vitello-vagiual  canals  and  gives  off  the  genito-intestinal  canal. 
This  canal  after  winding  in  a  double  loop  opens  into  the  intestine  on  the 
same  side  as  the  ovary.  It  was  empty  in  the  sectioned  worm.  The 
exteimal  openings  of  the  vaginae  are  situated  on  small  prominences 
ventro-lateral  in  position,  altho  there  is  a  single  large  opening  to  the 
exterior.  The  vitellaria  consist  of  masses  of  follicles  occupying  the  dor- 
sal and  lateral  areas  of  the  body.  They  form  a  sheet  of  gland  cells  on 
the  dorsal  side  of  the  body  posterior  to  the  testis.  They  are  somewhat 
reduced  along  the  median  dorsal  area  in  the  anterior  half  of  the  worm 
and  entirely  absent  onlj^  in  small  fields  over  the  testis  and  uterus.  They 
extend  along  the  sides  of  the  body  and  ventrally  are  limited  by  the  ceca. 
On  either  side,  at  the  level  of  the  ootype,  a  common  duct  from  the  longi- 
tudinal collecting  ducts  passes  ventrad  and  just  below  the  cecum  unites 
■wath  the  vagina  of  that  side  to  form  the  vitello-vaginal  canal  which 
discharges  into  the  ootype.  The  uterine  duct  leads  to  the  i;terus,  which 
in  each  of  the  specimens  contained  a  large  egg.  A  section  of  the  egg  is 
shown  in  Figure  23.  The  eggs  are  oval,  0.15  by  0.18  mm.,  and  in  the 
sectioned  worm  the  eg^  is  0.24  ram.  in  thickness.  From  the  uterus  a 
small  duet  passes  anteriad  and  ventrad,  opening  into  the  genital  atrium, 
posterior  and  ventral  to  the  cirrus  sac. 

The  excretory  system  agrees  with  the  general  description  given. 


319]  NORTH  AMERICAS  POLYSTOMIDAE—STUiXKARD  39 

The  descending  and  ascending  ducts  are  6  to  11^  in  diameter;  when 
emptj'  their  walls  collapse. 

P.  megacotijle  differs  from  all  known  American  forms  in  the  large 
number  of  hooks  present  in  the  genital  coronet,  and  in  this  character 
agrees  only  with  P.  ocellatum.  The  species  differs  from  P.  ocellatum, 
however,  in  the  difference  in  size  of  tlie  anterior  sucker  and  pharynx 
as  well  as  in  the  size  of  the  caudal  suckers.  P.  megacotyle  differs  from 
P.  mkrocotyle  in  the  number  of  genital  hooks  and  in  the  size  of  the 
posterior  suckers.  P.  megacotyle  has  a  larger  pharynx,  larger  caudal 
suckers,  and  a  larger  number  of  gental  hooks  than  P.  coronatum. 

POLYSTOMA   MICROCOTYLE    Stunkard  1916 
[Figures  28  and  29] 

This  species  is  described  from  a  single  specimen  from  the  mouth 
of  Chrysemys  marginata  from  Creston,  Iowa.  The  worm  was  stained 
and  moiuited  in  toto  (Fig.  28). 

It  is  3  mm.  long,  and  0.78  mm.  in  width.  The  caudal  disc  is  cordi- 
form,  1  mm.  in  width  at  the  level  of  the  anterior  suckers,  1.07  mm. 
thru  the  middle  pair,  and  0.74  mm.  thru  the  caudal  pair  of  suckers. 
Each  sucker  is  0.28  mm.  in  diameter  and  with  the  exception  of  the 
longer  distance  between  the  anterior  suckers,  they  are  separated  by 
almost  regular  equal  distances.  The  distance  between  the  anterior 
suckers  is  about  four  times  as  great  as  that  between  the  posterior  pair. 
Four  larval  booklets  are  present  between  the  two  anterior  suckers,  three 
in  a  row  but  with  their  hooks  pointing  in  different  directions,  and  the 
fourth  some  distance  posterior  to  the  others  (Fig.  29).  Between  the 
posterior  suckers  there  are  three  pairs  of  hooks :  the  pair  of  great  hooks, 
one  pair  of  larval  hooks,  and  a  third  pair  intermediate  in  size  between 
the  great  and  larval  hooks.  The  hooks  of  this  third  pair  are  the  same 
shape  as  the  great  hooks.  The  larval  hooks  are  0.017  mm.  long,  the 
gi-eat  hooks  are  0.116  mm.  long,  and  the  pair  intermediate  in  size  are 
0.061  mm.  long. 

In  this  specimen  as  the  suckers  are  small  the  musculature  of  the 
caixdal  disc  shows  very  plainly  (Fig.  29).  Muscle  strands  from  the 
ventral  side  of  the  body  and  others  from  the  body  wall  pass  to  the  bases 
of  each  of  the  suckers.  Others  pass  to  the  outside  of  the  dift'erent  suck- 
ers and  are  inserted  on  the  distal  and  intermediate  zones  of  the  suckers, 
serving  as  retractors  in  the  operation  of  the  organs.  Many  break  up 
into  smaller  fibers  and  can  not  be  traced.  From  the  base  of  each  sucker 
the  muscles  spread  out  in  a  fan  shaped  manner  and  fibers  can  be  traced 
not  only  to  the  large  strands  from  the  body  wall  but  also  small  fibers 


40  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [320 

pass  from  the  base  of  each  sucker  to  each  of  the  other  suckers,  ilan.y 
of  the  muscles  brancli  and  ramify  thru  tlie  tissue  of  the  disc. 

The  anterior  sucker  is  0.2  mm.  long  and  0.42  mm.  wide ;  the  pharynx 
is  0.37  mm.  long  and  0.4  mm.  in  width.  No  esophagus  is  visible  in  the 
single  toto  preparation  and  only  the  anterior  part  of  the  intestine  can 
be  seen. 

The  testis  is  slightly  anterior  to  the  middle  of  the  body;  it  is  oval, 
0.36  mm.  in  length  and  0.42  mm.  in  width.  The  sperm  duct  can  be 
traced  dorsally  and  anteriorly;  cephalad  of  the  ovary  it  expands  into 
a  seminal  vesicle  which  stains  deeply  due  to  the  presence  of  spermatozoa. 
The  genital  coronet  contains  thirty-two  hooks,  equal  in  size  and  similar 
in  shape. 

The  ovary  is  on  the  left  side  of  the  body,  about  midway  between 
the  testis  and  the  genital  pore.  The  oviduct  arises  at  the  median  pos- 
terior margin  and  passes  mediad,  but  the  structure  of  the  ootype  could 
not  be  made  out.  The  uterus  can  be  distinguished  at  the  level  of  the 
ovary  on  the  opposite  side  of  the  bodj'  aud  is  empty.  Laterally  the 
vaginae  are  visible  and  the  vitello-vaginal  canals  can  be  traced  mediad 
a  short  distance  from  the  ceca.  The  vitellaria  are  .strongly  developed, 
anteriorly  they  extend  to  the  middle  of  the  pharynx,  and  posteriorly 
to  the  caudal  disc.  There  is  a  strand  of  follicles  across  the  body  from 
side  to  side  between  the  pharynx  and  the  level  of  the  genital  pore.  The 
follicles  occupy  the  dorsal  and  lateral  regions  of  the  body  but  anteriorly 
are  reduced  in  the  median  area  and  are  absent  in  the  fields  over  the 
testis  and  ovary.  They  obscure  the  ceca  caudal  to  the  testis.  No  vitel- 
line ducts  were  seen. 

The  excretory  vesicles  appear  one  on  either  side  of  the  body  dor- 
sally,  at  the  level  of  the  bifurcation  of  the  intestine. 

In  number  of  genital  hooks  this  specimen  agrees  only  with  P.  coro- 
iwtmn  Leidy.  A  comparison  with  a  type  specimen  of  P.  coronatum 
shows  that  in  the  latter  form  the  pharynx  and  testis  are  much  smaller 
and  the  suckers  of  the  caudal  disc  are  much  larger. 

POLYSTOMA   CORONATUM   Leidy  1888 
[Figure  27] 

This  description  was  made  from  a  single  type  specimen  from  the 
United  States  National  Museum.  The  worm  was  stained  and  mounted 
in  toto. 

Leidy  (1888)  says  the  host  is  the  common  food  terrapin,  and  the 
previous  year,  speaking  of  eating  terrapin,  he  mentions  Emys  ijalustris 
and  Emys  rugosa.     Braun   (1879-1893)   lists  the  species  from  Cistudo 


321]  XORTH  AMERICAX  POLVSTOMIDAE—STUXKARD  41 

Carolina.  Goto  (1899)  in  discussing  the  specimen  described  by  Leidy 
as  P.  ohlongum,  refers  to  the  food  terrapin  as  E.  rugosa. 

Leidy  gives  no  figure  and  his  description  states:    "Polystomum  coro- 

natum Body  when  elongate  lanceolate.    Caudal  disc  wider 

than  the  body,  cordiform,  with  three  pairs  of  bothria  and  with  the  body 
attached  between  the  anterior  two  pairs;  changeable  in  form  to  oblong, 
circular  or  quadrate ;  with  three  pairs  of  minute  hooks  between  the 
anterior  part  of  bothria  and  with  a  larger  pair  and  two  smaller  pairs 
between  the  last  pair  of  bothria.  Genital  aperture  with  a  circular  or 
transverse  oval  coronet  of  thirty-two  hooks  of  equal  length.  No  eyes 
visible.  Length,  elongated  from  4  to  6  mm ;  contracting  to  about  half 
the  length  and  widening  proportionately." 

The  specimen  from  wliieh  the  present  description  was  made  (Fig. 
27)  is  3.15  mm.  long  and  0.83  mm.  in  width.  The  greatest  width  is  at 
the  level  of  the  vaginae ;  the  body  tapers  rapidly  anteriorly,  widening 
again  slightly  at  the  anterior  sucker.  From  the  level  of  the  vaginae 
the  body  gradually  grows  narrower  posteriorly  to  its  insertion  into  the 
caudal  disc.  The  disc  is  1.24  mm.  wide  at  the  level  of  the  anterior 
suckers,  1.2  mm.  thru  the  middle  pair  and  0.78  mm.  thru  the  caudal  pair 
of  suckers.  Each  sucker  is  approximately  0.37  mm.  in  diameter,  and 
constructed  as  previously  described.  There  are  thirty-two  small  di- 
visions in  the  peripheral  cuticular  band  of  the  only  sucker  in  which  they 
could  be  counted.  The  disc  bears  the  usual  eighteen  hooks ;  the  six 
larval  booklets  at  the  anterior  margin  of  the  disc  are  situated  in  a  row 
equidistant  from  the  anterior  edge  of  the  disc,  the  two  lateral  hooks 
on  either  side  are  nearer  each  other  than  the  more  centrally  located  one 
is  to  the  median  one  of  that  side.  Larval  booklets  are  present  in  the 
bases  of  the  suckers  and  one  pair  is  present  between  the  caudal  suckers. 
Between  the  caudal  suckers  there  are  present  also  both  a  pair  of  great 
hooks  and  a  third  pair  intermediate  in  size  between  the  two.  The  larval 
booklets  are  0.02  mm.  in  length,  tlie  hooks  of  intermediate  size  are  0.051 
mm.,  and  the  great  hooks  are  0.132  mm. 

The  anterior  sucker  is  oval,  0.16  mm.  long  and  0.4  mm.  wide ;  the 
pharynx  is  circular  in  outline,  0.3  mm.  in  diameter.  No  esophagus  can 
be  seen  in  the  toto  preparation  and  behind  the  posterior  margin  of  the 
testis  the  ceca  are  obscured  by  the  vitellaria. 

The  testis  is  slightly  anterior  to  the  center  of  the  body,  circular  in 
outline,  and  0.3  mm.  in  diameter.  The  vas  deferens  could  not  be  distin- 
guished; the  cirrus  sac  in  ventral  aspect  is  0.19  mm.  in  diameter;  the 
genital  coronet  contains  thirty-two  hooks,  similar  in  size  and  shape,  the 
shanks  being  sickle-shaped. 

The  ovary  is  situated  on  the  right  side  of  the  body,  about  its  own 


42  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [322 

diameter  anterior  to  the  testis ;  in  ventral  view  it  is  circular,  0.094  mm. 
in  diameter.  The  oviduct  passes  posteriad  and  mediad,  and  the  ootype 
appears  as  a  darkly  stained  area.  The  vaginae  can  be  distinctly  seen 
and  laterad  of  the  ceca  on  either  side  there  is  a  large  cavity  communi- 
cating with  the  exterior.  The  uterus  is  empty;  the  folded  walls  of  the 
cavity  are  visible  on  the  left  side  of  the  body.  The  vitellaria  are  strongly 
developed.  Masses  of  follicles  occupy  the  dorsal  and  lateral  regions  of 
the  body  biit  ventrally  do  not  extend  mediad  of  the  ceca.  Anteriorly 
they  extend  to  the  region  of  the  pharynx ;  there  is  a  strand  across  the 
body  just  behind  the  pharynx  and  in  the  intercecal  area  anterior  to  the 
testis  they  are  largely  interrupted,  permitting  the  structures  in  this 
region  to  be  made  out.    None  of  the  vitelline  ducts  are  visible. 

The  excretory  vesicles  are  anterior  to  and  slightly  laterad  of  the 
ceca  at  the  level  of  the  caudal  margin  of  the  pharynx,  but  no  ducts 
could  be  seen. 

POLYSTOMA    HASSALLI    Goto  1899 
[Figures  30  to  33] 

This  species  was  described  by  Goto  (1899)  from  the  urinary  blad- 
der of  Cinosternum  pennsylvanicum  from  Maryland.  The  writer  has 
since  collected  the  species  from  other  hosts  and  localities.  A  single 
specimen  was  found  in  the  urinary  bladder  of  Aromochehjs  carinatus 
from  Newton,  Texas;  five  were  collected  from  the  iirinary  bladder  of 
Aromochehjs  odoratus  from  Ealeigh,  North  Carolina;  two  from  the 
urinar}-  bladder  of  Cinosternum  pennsylvanicum  from  Raleigh,  N.  C; 
and  three  from  the  urinary  bladder  of  Chelydra  serpentina  from  Walker, 
Iowa. 

The  worms  (Figs.  30,  31)  vary  from  1.3  to  2  mm.  in  length  and 
from  0.4  to  0.65  mm.  in  width.  The  caudal  disc  varies  in  shape  from 
hexagonal  to  cordiform  and  is  of  approximately  the  same  width  as  the 
body.  The  suckers  are  0.12  to  0.16  mm.  in  diameter.  The  eighteen 
hooks  of  the  caiidal  disc  have  the  iisual  arrangement  and  are  described 
by  Goto.  HoM'ever,  he  reports  the  larval  hooks  as  being  0.33  mm.  in 
length  and  the  great  hooks  between  the  caudal  suckers  as  0.125  mm.  in 
length.  This  is  evidently  a  typographical  error,  since  he  figured  the 
great  hooks  as  about  four  times  the  size  of  the  small  ones.  In  the  pres- 
ent material  the  great  hooks  are  the  same  length  as  stated  by  Goto  and 
tlie  smaller  ones  are  0.033  mm.  in  length,  which  agrees  with  the  figures 
of  Goto  bj'  a  change  of  one  place  in  the  decimal  point. 

Tlie  anterior  sucker  is  ovoid,  more  pointed  anteriorly.  It  may  be 
longer  in  either  the  anterior-posterior  or  lateral  axis  and  varies  in  diame- 
ter from  0.22  to  0.33  mm.    The  pharynx  is  spherical  or  oval  and  varies 


323]  NORTH  AMERICAN  POLYSTOMIDAE—STUNKARD  43 

in  width  from  0.1  to  0.14  mm. ;  it  may  be  longer  in  either  axis.  There 
is  no  esophagus,  but  in  some  specimens  a  median  pocket  of  the  intestine 
extends  anteriad  from  the  bifurcation  to  the  pharynx.  In  others,  and 
this  is  a  more  usual  condition,  lateral  pockets  of  the  intestine  extend 
anteriad,  one  on  either  side  of  the  pharynx  (Fig.  33).  The  anterior 
sucker  and  pharynx  are  lined  with  cuticula;  the  intestine  with  the 
usual  digestive  epithelium.  In  those  specimens  in  which  the  uterus 
contains  an  egg,  the  large  size  of  the  egg  causes  the  ceca  to  be  widely 
separated  at  the  uterine  level  and  they  approach  each  other  behind  the 
uterus.  In  one  specimen,  median  branches  from  the  two  ceca  fuse  and 
form  a  posterior  connection  of  the  diverticula  (Fig.  30),  and  in  another 
the  two  ceca  are  united  at  their  ends. 

The  testis  is  situated  ventrally,  just  behind  the  middle  of  the  body. 
It  is  a  somewhat  shapeless  mass,  roughly  oval  in  outline,  crosswise  of 
the  body,  extending  between  the  ceca  just  posterior  to  the  uterus.  The 
vas  deferens  passes  anteriad,  dorsal  to  the  ovary  and  between  it 
and  the  uterus;  anterior  to  the  uterus  the  sperm  duct  turns  ventrad, 
enlarges  to  form  a  seminal  receptacle,  and  then  passes  thru  the  cirrus 
sac,  opening  into  the  genital  atrium  (Fig.  32).  The  cirrus  hooks  are 
sixteen  in  number,  0.028  mm.  in  lengtli,  straight,  and  with  a  wing  like 
process  at  the  middle  as  described  by  Goto. 

The  ovary  is  comma  shaped  or  ovoid  in  outline,  situated  obliquely 
in  the  body,  on  either  the  right  or  left  side.  Typically  the  ovary  is  on 
one  side  of  the  body  and  the  uterus  on  the  other,  but  the  enormous  size 
of  the  egg  causes  the  uterus  to  occupy  a  more  or  less  central  position, 
crowding  the  ovary  far  to  one  side.  The  ovary  is  0.058  by  0.065  mm. 
in  the  smallest  and  0.085  by  0.12  mm.  in  the  largest  worms,  altho  the 
size  of  the  ovary  does  not  correspond  precisely  with  the  size  of  the 
worm.  The  oviduct  arises  at  the  dorsal  median  and  posterior  part  of 
the  ovary  and  after  a  dorsal  loop  it  turns  posteriad  and  ventrad  to  open 
into  the  ootype.  Mehlis'  gland  is  present.  The  genito-intestinal  canal 
branches  from  the  ootype  and  after  a  short  winding  course  opens  into 
the  intestine  near  the  ovary.  From  the  ootype,  the  uterine  duct  passes 
laterally  to  the  opposite  side  of  the  median  line  and  then  anteriorly 
and  dorsally  to  open  into  the  dorsal  posterior  part  of  the  uterus.  The 
vitellaria  extend  from  the  pharyngeal  region  to  the  anterior  margin 
of  the  caudal  disc;  there  is  a  row  of  follicles  across  the  dorsal  surface 
behind  the  pharynx  but  they  are  absent  between  the  ceca  anterior  to 
the  testis.  According  to  Goto,  "lobes  not  very  numerous,  separated 
from  one  another,  mostly  confined  to  the  lateral  portion  of  the  body, 
but  also  present  in  the  median  portion  behind  the  testis."  The  vaginae 
are  ventro-lateral,  midway  between  the  anterior  and  posterior  ends  of 
the  body.    There  are  no  vaginal  prominences,  the  vaginal  openings  are 


44  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [324 

single,  aud  internally  they  unite  with  ducts  from  the  longitudinal  vitel- 
line ducts  to  form  the  viteUo-vaginal  canals,  as  described  for  the 
other  species.  They  do  not  open  separately  into  the  ootype,  but  the 
two  vitello-vaginal  canals  open  into  a  common  reservoir  from  which  a 
duct  passes  dorsad  and  discharges  into  the  ootype  (Fig.  32).  In  a  few 
of  the  specimens  the  uterus  is  empty  aud  in  others  it  contains  a  single 
large  egg,  the  size  of  which  varies  within  wide  limits.  The  smallest 
eggs  are  0.11  by  0.25  mm.  and  the  largest  0.18  by  0.34  mm.  The  pos- 
terior edge  of  the  uterus  is  at  the  level  of  the  vaginae,  and  anteriorly 
there  is  a  small  duct  from  the  uterus  to  the  ventral  posterior  part  of 
the  genital  atrium.  The  genital  pore  is  in  the  median  line,  a  short 
distance  posterior  to  the  bifurcation  of  the  alimentary  tract. 

The  excretory  pores  are  slightly  more  posteriorly  situated  than  in 
the  previous  described  species.  Descending  and  ascending  ducts  occupy 
the  characteristic  positions. 

POLYSTOMA  OBLONGUM  Wright  1879 

This  species  was  described  by  Wright  (1879)  from  the  urinary 
bladder  of  Aromochelys  odoratus.  I  have  had  no  opportunity  to  work 
on  material  of  the  species  and  the  following  discussion  is  based  on  the 
description  of  Wright.  According  to  that  author  P.  oblongum  measures 
up  to  2.5  mm.  in  length  and  1.5  mm.  in  width.  The  body  is  oblong  in 
shape,  tho  capable  of  considerable  variation.  The  caudal  lamina  is  some- 
what narrower  than  the  greatest  width  of  the  body  and  is  shorter  than 
broad.  The  arrangement  of  the  suckers  and  hooks  is  similar  to  that  in 
P.  integerrimum;  the  suckers  are  0.2  mm.  in  diameter;  the  large  hooks 
are  0.15  mm.  and  the  small  hooks  are  0.015  mm.  in  length. 

The  mouth  is  on  the  ventral  surface  of  the  rounded  anterior  end. 
The  pharyux  is  bowl-shaped  and  the  intestinal  ceca  are  without  anasto- 
moses or  branches.  The  description  of  the  excretory  system  is  very 
meager;  concerning  it  he  says  that  only  the  convoluted  lateral  stems 
were  observed  near  the  anterior  end. 

The  testis  is  situated  in  the  posterior  third  of  the  body,  the  vas 
deferens  passing  dorsad  and  anteriad  to  the  genital  pore,  which  lies  im- 
mediately behind  the  bifurcation  of  the  intestine.  The  cirrus  coronet  is 
described  as  consisting  of  sixteen  alternately  large  and  small  hooks.  The 
free  end  of  each  is  sharply  curved,  while  the  attached  end  is  shaped  like 
a  cross  the  transverse  piece  of  which  is  longer  on  one  side  than  the  other. 
The  longer  pieces  measure  20/<.  and  the  shorter  ones  15ja. 

Doubt  is  expressed  concerning  the  disposition  and  relations  of  tlie 
female  organs.  The  ovary  is  described  as  situated  in  front  of  the  testis 
on  the  right  side  of  the  body,  but  it  seems  probable  that  the  organ  figured 


325]  NORTH  AMERICAN  POLYSTOMIDAE-STUN KARD  45 

as  the  "  (shell  gland?) "'  is  really  the  ovaiy.  The  lobes  of  the  vitellaria 
are  scattered  and  extend  from  the  pliarynx  to  the  caudal  lamina  or  disc. 
It  is  doubtful  whether  Wright  was  correct  in  his  statement  that  "The 
transverse  duct  seemed  to  pass  inward  dorsally  from  the  intestinal  ceca," 
since  in  all  other  known  species  the  vitelline  ducts  are  ventral  in  position. 

The  uterus  is  described  as  containing  a  single  large  egg  or  embryo. 
The  egg  shell  is  thin  and  is  destitute  of  the  short  stump  present  in  that 
of  P.  integcrrimitm,  but  has  a  rather  large  operculum.  In  two  cases  the 
embryo  had  already  escaped  from  the  shell  and  moved  actively  within 
the  uterine  chamber.  It  is  a  Gyrodactylus-like  larva,  similar  to  that  of 
P.  integerrimum,  with  eye  spots  disposed  in  the  same  fashion.  It  is 
devoid  of  cilia,  and  movement  seemed  to  depend  entirely  on  the  muscles 
and  hooks  of  the  caudal  disc.  The  latter  had  a  rounded  outline  except 
posteriorly  where  there  was  a  square  projection  bearing  the  four  small 
posterior  hooks.  The  disc  measured  0.114  mm.  across  and  the  twelve 
small  anterior  hooks  were  disposed  at  regular  intervals  on  the  margin  of 
the  rounded  part.  There  was  no  trace  of  suckers.  The  small  hooks  had 
already  attained  their  definitive  size  and  form.  The  two  large  hooks 
were  situated  considerably  further  in  from  the  margin  than  in  the  adult, 
and  measured  only  0.024  mm.  instead  of  0.15  mm.  in  length,  which  dif- 
ference it  is  stated  was  due  to  the  shortness  of  the  immersed  portion,  in 
which,  however,  the  notch  was  already  formed. 

In  shape,  as  well  as  relative  position  and  size  of  organs,  P.  oblangmn 
strongly  resembles  P.  hassalli.  It  is  significant  also  that  both  are  from 
the  urinary  bladder  of  AromocheUjs  odoratus.  P.  oblongum  is  slightly 
longer  and  broader  than  P.  hassalli,  the  posterior  suckers  are  larger  and 
the  small  hooks  of  the  disc  are  only  about  half  the  length  of  those  in 
those  in  P.  lutssalli.  The  two  species  agree  in  number  of  genital  hooks, 
but  in  the  former  species  the  hooks  are  alternately  large  and  small  and 
with  the  free  end  sharply  curved,  while  in  P.  hassalli  they  are  straight 
and  luiiform  in  size. 

The  species  in  the  genus  Polystoma  have  been  arranged  in  the  form 
of  an  analytical  key  utilizing  the  more  prominent  or  more  useful 
diagnostic  structures  in  separating  the  different  forms.  This  key  is 
found  on  the  following  page. 


46  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [326 

KEY  TO  THE  SPECIES  OP  THE  GENUS  POLTSTOMA 

Uterus  long,  contains  many  eggs 2 

Great  hooks  present  on  the  caudal  disc 3 

Ceca  branching P.  integerrimuni 

Ceca  not  branching  _ P.  hulliense 

Great  hooks  not  present  on  caudal  disc P.  alluaudi 

Uterus  short,  contains  a  single  egg 7 

Great  hooks  present  on  caudal  disc _     8 

Genital  hooks  of  equal  length 9 

Not  more  than  sixteen  genital  hooks 10 

Genital  hooks  eight  in  number; 

ectoparasitic  form  P.  integerrimuni 

Genital  hooks  sixteen  in  number P.  hassalli 

Genital  hooks  more  than  sixteen  in  number „ _  13 

Genital  hooks  thirty-two  in  number.... _ 14 

Caudal  suckers  large,  adjacent  but  not  contiguous, 

pharynx,  smaller  than  anterior  sucker P.  coronatum 

Caudal  suckers  small,  widely  separated,  pharynx  equal  in 

size  to  anterior  sucker P.  microcotyle 

Genital  hooks  more  than  thirty-two  in  number 17 

Testis  simple _ ~ — 18 

Caudal  suckers  large,  overlap P.  megacotyle 

Caudal  suckers  small,  separated P.  ocellatum 

Testis  branched  J",  kachugae 

Genital  hooks  unequal  in  length JP.  oblongum 

Great  hooks  of  caudal  disc  reduced  or  absent 23 

Genital  hooks  sixteen  in  number P.  oriictdare 

Genital  hooks  thirty-two  in  number....„ _ — — P.  opacum 


1 

6) 

2 

'   5) 

3 

'  4) 

4 

3) 

5 

'  2) 

6 

1) 

7 

22) 

8 

21) 

9 

12) 

10 

11) 

11 

10) 

12 

9) 

13 

16) 

14 

15) 

15 

14) 

16 

13) 

17 

20) 

18 

19) 

19 

18) 

20 

17) 

21 

8) 

22 

7) 

23 

24) 

24 

23) 

327]  NORTH  AMERICAN  ASPJDOGASTRIDAE—STCNKARD 


ASPIDOGASTRIDAE 

Because  of  its  peculiar  multiloeulate  adhesive  apparatus,  Burmeister 
(1856)  called  attention  to  the  difference  between  the  genus  Aspidogaster 
and  the  remainder  of  the  trematodes,  and  suggested  a  division  of  the 
Trematoda  into  (1)  Malacobothrii  for  the  distomes  and  holostomes, 
(2)  Pectobothrii  for  the  polystomes,  and  (3)  Aspidobothrii  for  Aspido- 
gaster. Subsequent  writers  however  continued  to  include  Aspidogaster 
with  the  polystomes  until  Monticelli  (1892)  revived  the  classification 
of  Burmeister,  but  named  the  three  suborders  into  which  he  divided  the 
trematodes,  Heterocotylea,  Aspidocotylea,  and  Malacocotylea. 

In  the  classification  of  Monticelli,  the  Aspidocotylea  contained  the 
single  family  Aspidobothridae.  Poche  (1907)  proposed  to  make  the 
name  of  the  family  agree  with  the  rules  of  zoological  nomenclature 
according  to  which  "The  name  of  the  family  is  formed  by  adding  the 
ending  -idae  to  the  stem  of  the  name  of  its  type  genus. ' '  Thus  the  name 
of  the  family  must  become  Aspidogastridae. 

The  family  is  of  special  interest  to  students  of  trematode  mor- 
phology. The  form  of  the  adhesive  apparatus,  with  its  retractile  mar- 
ginal organs,  the  separation  of  the  body  into  dorsal  and  ventral  portions 
by  a  muscular  partition,  the  sac-like  alimentary  tract,  and  the  details 
of  the  genital  organs  are  peculiar  to  the  group.  The  family  contains 
both  ectoparasitic  and  endoparasitic  species,  forms  with  direct  develop- 
ment and  at  least  one  species  which  has  an  intermediate  host,  while  the 
hosts  infested  by  the  adult  parasites  include  both  invertebrates  and 
vertebrates,  species  having  been  reported  from  molluscs,  fishes,  and 
turtles. 

Summaries  or  revisions  of  the  group  have  been  made  by  Diesing 
(1850,  1859),  Taschenberg  (1879),  Hoyle  (1888),  Moutieelfi  (1892), 
Braun  (1879-1893),  and  Nickerson  (1902). 

Only  three  species  representing  two  genera  of  the  family  are  known 
from  North  America,  Aspidogaster  conchicola  von  Baer  1827,  Cotylaspis 
insignis  Leidy  1856,  and  Cotylaspis  cokeri  Barker  and  Parsons  1914. 
Representatives  of  each  of  these  species  were  available  for  the  present 
study.  The  first  two  species  are  well  known;  concerning  A.  conchicola 
no  further  data  were  obtained,  but  a  few  corrections  are  made  to  former 
descriptions  of  C.  insignis. 


48  ILUXOIS  BIOLOGICAL  MONOGRAPHS  [328 

Cotyl<ispis  cokeri  has  been  mentioned  but  once  in  print,  but  on  the 
basis  of  extended  studies  this  form  had  been  fully  described  and  its 
position  as  a  new  species  demonstrated  in  a  thesis  submitted  by  the 
writer  in  partial  fulfillment  for  the  degree  of  Master  of  Arts  in  the 
Graduate  school  of  the  University  of  Illinois  in  June  1914.  The  fol- 
lowing October  Barker  and  Parsons  (1914),  having  also  been  working 
on  this  form  independently,  published  a  brief  description  naming  it 
Cotylaspis  cokeri.  Since  I  liad  completed  my  work  on  it  before  the 
appearance  of  their  note  and  the  publication  of  their  final  report  has 
been  delayed  it  seems  proper  to  give  here  a  detailed  description  of  the 
species. 

ASPIDOGASTER    CONCHICOLA   von  Baer  1827 

About  fifty  specimens  from  the  pericardial  and  renal  cavities  of 
Andonta  corpidenta  from  Havana,  Illinois,  and  a  similar  number  of 
specimens  from  the  same  organs  of  Quadrula  undulata  from  North 
Judsou,  Indiana,  constitute  the  material  of  this  species  available  for 
study. 

A  detailed  comparison  of  these  specimens  with  the  descriptions  of 
A.  conchicola  as  given  by  Voeltzkow  (1888),  Stafford  (1896),  and  other 
writers,  shows  that  they  belong  to  that  species  and  substantiates  the  obser- 
vations of  Leidy  (1851),  Kelly  (1899),  and  Kofoid  (1899),  that  A.  con- 
chicola occurs  in  this  country.  So  far  it  is  the  only  species  in  the  genus 
known  from  molluscan  hosts. 

Kelly  (1899)  made  a  parasitological  examination  of  1537  individ- 
uals of  forty-foiir  species  of  unios  from  Mt.  Vernon,  Iowa,  Havana, 
Illinois,  and  Lewisburg  and  Phoenixville,  Pennsylvania,  and  included 
in  his  report  results  of  the  examination  of  sevent.y-seven  individuals 
belonging  to  eighteen  species,  made  by  Kofoid  in  1895  and  1896.  In 
four  hundred  thirty-five  cases  A.  conchicola  was  found  in  the  pericar- 
dium only,  in  seventy-five  in  the  kidneys  only,  and  in  one  hundred 
thirty-four  cases  both  cavities  contained  the  parasite.  The  presence  of 
the  mature  trematode  in  the  pericardium  and  of  eggs  within  the  nephri- 
dia  was  not  infrequent.  Of  the  1537  specimens  examined,  forty-one 
per  cent  were  parasitized  with  A.  conchicola  and  thirty-seven  of  the 
forty-four  species  were  infested  with  the  parasite. 

No  further  data  on  this  species  were  obtained  by  the  present  study. 


329]  NORTH  AMERICAN  ASPIDOGASTRIDAE—STUSKARD  49 

COTYLASPIS    INSIGNIS   Leidy  1856 
[Figure  56] 

The  material  of  this  species  consists  of  specimens  from  Anodonta 
imbecilis,  A.  corpulenta,  Lampsilis  gracilis,  and  Vnio  pustulosis  from 
Havana,  Illinois,  and  others  from  Anodonta  ferrus  and  A.  ovata  from 
Reed's  Lake  near  Grand  Rapids,  Michigan.  The  material  proved  to 
belong  to  the  same  species  and  was  identical  with  C.  insignis  Leidy. 

Leidy  first  discovered  the  parasite  in  the  Unionidae  of  the  Schuyl- 
kill River  and  founded  the  genus  to  receive  the  new  species.  His  generic 
and  specific  diagnosis  (1858)  follows:  "Body  curved  infundibuliform, 
anteriorly  cylindro-conical,  posteriorly  expanding  into  a  subcircular  or 
oval  ventral  disc  with  numerous  acetabula  arranged  iu  a  triple  series. 
Mouth  infero-tei'minal,  with  prominent  upper  lip,  and  protractile  into 
a  cup  or  disc  like  acetabulum.  Intestinal  apparatus  as  in  Aspidogaster, 
eyes  two,  distinct,  black,  situated  on  either  side  of  the  head.  Generative 
apertures  inferior  between  the  head  and  ventral  disc." 

According  to  the  same  author,  C.  insignis,  the  type  species  is: 
"Translucent  white  or  pink  white,  upper  lip  snout  like,  conical,  ventral 
disc  crenate  at  the  margin :  acetabula  twenty-nine,  oblong  quadrate,  the 
outer  rows  continuous  in  front  and  behind  forming  a  circle.  Length 
from  one-half  to  one  line ;  ventral  disc  from  one-fourth  to  one-half  line 
in  diameter.  Adheres  to  the  outer  surface  of  the  renal  organ  and 
upper  margin  of  the  foot,  within  the  cleft  of  the  upper  branchial  cavity 
of  Anodonta  fluviatilis  and  A.  lacustris." 

Forbes  (1896)  reported  this  parasite  in  the  river  clams  at  Havana, 
Illinois.  Osborn  (1898)  described  the  species  from  Lake  Chautauqua, 
New  York,  as  Platyaspis  anadontac.  Kofoid  (1899)  corrected  this 
error,  demonstrating  that  Leidy 's  genus  is  entitled  to  recognition,  and 
establishing  the  specific  identity  of  Platyaspis  anadontac  Osborn  with 
C.  insignvi  Leidy.  Kelly  (1899)  reporting  on  the  examination  of  over 
sixteen  hundred  individuals  of  forty-four  species  of  Unionidae  found  the 
parasitt'  in  twenty-four  different  species  of  molluscs  and  in  eighteen  per 
cent  of  the  individuals  examined. 

Osborn  (1904)  gives  a  review  of  the  literature,  an  account  of  the 
distribution,  habits,  external  and  internal  anatomy  of  the  mature  worm, 
and  a  description  of  a  very  young  individual.  The  young  specimen 
described  has  a  simple  ventral  sucker,  no  eye  spots,  no  marginal  organs, 
two  entirely  distinct  excretory  systems,  and  wholly  separate  pores.  This 
condition  of  the  excretory  system  is  compared  with  the  condition  in 
redia  and  eercaria  and  according  to  Osborn  favors  the  idea  suggested 
by  Leuckart  that  the  Aspidogastridae  are  sexually  mature  redia. 


so  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [330 

COTYLASPIS    COKERI   Barker  and  Parsons  1914 
[Figures  46  to  55,  57,  58] 

From  four  to  twenty-five  specimens  were  found  in  the  intestine 
of  each  of  seven  specimens  of  Malacoclemmys  lesueurii  from  Newton, 
Texas. 

The  worms  (Figs.  46,  47,  52)  average  1.5  mm.  in  length  by  0.7 
mm.  in  width,  altho  there  is  considerable  variation  in  relative  length 
and  width  due  to  the  movements  of  the  animal.  The  body  is  composed 
of  two  parts,  an  anterior  dorsal  forebody  and  a  posterior  ventral  adhe- 
sive disc.  When  extended  (Fig.  46),  the  forebody  has  the  shape  of  a 
cornucopia,  the  larger  end  attached  obliquely  to  the  central  two-thirds 
of  the  dorsal  surface  of  the  adhesive  disc.  In  this  condition  the  worm 
has  an  elongate  form,  projecting  beyond  the  adhesive  disc  a  distance 
equal  to  the  length  of  that  structure:  in  a  retracted  condition  (Fig.  52) 
it  is  compact  and  may  not  project  beyond  the  disc.  The  total  length 
of  the  worm  varies  therefore  with  the  state  of  extension  of  the  forebody, 
from  the  length  of  the  adhesive  disc  to  twice  that  distance. 

The  adhesive  disc  (Figs.  47,  57)  is  a  muscular  organ,  a  multilocu- 
late  sucker,  used  for  attachment  and  locomotion.  It  has  a  crenate  oval 
outline,  the  dorsal  surface  is  arched,  and  the  ventral  surface  is  flattened. 
The  ventral  surface  is  divided  by  two  longitudinal  and  eleven  cross 
ridges  into  thirty-two  aeetabula,  which  are  arranged  in  three  rows; 
there  are  twenty-two '  peripheral  alveoli  enclosing  ten  median  alveoli. 
In  this  statement,  the  alveolus  at  either  end  is  counted  in  the  peripheral 
rather  than  the  median  row,  tho  in  location  included  in  both.  These 
compartments  change  in  shape  with  the  movements  of  the  animal,  be- 
coming oval  or  quadrangular.  The  shape  and  size  of  the  disc  are  rela- 
tively constant,  measurements  of  the  disc  in  twenty  mounted  toto  speci- 
mens vary  only  from  1.2  to  1.4  mm.  in  length  and  from  0.58  to  0.78 
mm.  in  width.  This  structure  recalls  the  molluscan  foot,  and  it  has 
often  been  termed  the  foot  altho  the  morphological  comparison  is  not 
precise. 

Movement  consists  of  extension  of  the  forebody,  which  furthermore 
may  be  turned  in  any  direction,  and  in  the  less  striking  and  more  re- 
stricted movement  of  the  disc.  The  disc  has  a  tendency  to  turn  up  at 
the  edges,  especially  at  the  anterior  and  posterior  ends.  In  adhesion 
the  organ  may  act  as  a  unit,  or  the  separate  alveoli  may  function  inde- 
pendently. In  locomotion  there  is  a  regular  series  of  movements,  the 
forebody  is  extended  and  attached  by  the  sucking  action  of  the  mouth 
funnel,  then  the  disc  is  loosened  and  the  forebody  contracted,  bringing 
the  anterior  part  of  the  disc  near  the  mouth,  when  the  disc  is  attached 


331]  KORTH  AMERICAS  ASPIDOGASTRIDAESTVSKARD  51 

and  the  series  of  movements  repeated.  The  worm  moved  rapidly  across 
the  field  of  the  microscope. 

Body  Covering. — Externally  the  worms  are  covered  by  a  non- 
cellular  cuticiila,  which  is  thickest  on  the  dorsal  side  of  the  body  and 
thinnest  on  the  ventral  surface  of  the  adhesive  disc  (Figs.  49,  53).  It 
is  without  hooks  or  spines,  and  on  the  dorsal  surface  reaches  a  thickness 
of  5/i,  while  on  the  ventral  surface  of  the  disc  it  is  only  about  Iju.  in 
thickness.  The  cuticula  is  turned  in  at  the  external  openings  and  lines 
the  external  portions  of  the  canals  of  the  alimentary,  excretory  and 
reproductive  systems. 

Musculature. — Immediately  inside  the  cuticula  is  the  tlireo  layered 
dermo-muscular  wall,  circular  longitudinal  and  oblique  muscles  occur- 
ring in  the  order  mentioned,  the  circular  lying  next  to  the  cuticula 
and  in  all  parts  of  the  wall  being  better  developed  than  the  others.  The 
musculature  is  delicate  and  in  some  places  the  longitudinal  and  oblique 
muscles  are  very  scanty.  The  musculature  of  the  ventral  side  of  the 
forebody  is  continued  posteriorly  in  a  thin  sheet,  the  so-called  septum 
or  diaphragm  (Fig.  53),  which  lies  just  above  the  limiting  membrane 
of  the  musculature  of  the  disc  and  extends  posteriad  as  far  as  the  caudal 
end  of  the  cirrus  sac.  In  C.  insignis  Osboru  described  this  structure 
as  passing  posteriad  as  far  as  the  caudal  end  of  the  ovary  and  in  other 
genera  it  is  more  strongly  developed.  The  parenchymous  muscles  of 
the  body  are  long,  often  much  branched,  and  most  abundant  in  locations 
where  they  connect  different  parts  of  the  body  wall  with  each  other  or 
w-ith  adjacent  internal  structures.  In  the  anterior  part  are  many  well 
developed  muscles  of  this  type  used  in  the  movement  of  that  region. 
Running  longitudinally  among  the  vitellaria,  as  well  as  dorso-ventrally 
among  the  viscera  there  are  many  muscle  fibers.  Sphincters  and  dilators 
occur  at  the  genital  pore,  excretorj'  pore,  at  the  base  of  the  mouth  funnel, 
and  at  the  opening  between  the  pharynx  and  the  intestine. 

The  disc  is  separated  from  the  forebody  by  a  limiting  membrane 
(Figs.  49,  53).  This  membrane  runs  parallel  to  the  general  course  of 
the  external  ventral  surface  of  the  disc,  projecting  ventrad  at  each 
ridge.  Extending  between  this  membrane  and  the  external  wall  there 
are  muscle  fibers,  often  mvu?h  branched  especially  at  the  ends.  The 
ventral  projections  of  the  limiting  membrane  into  tlie  ridges  of  the 
disc  form  two  sides  of  long  triangular  prisms,  which  extend  longitudi- 
nally and  transvei'sely  above  the  musculature  of  the  disc.  One  face 
of  each  of  these  prisms  is  dorsal  and  the  opposite  angles  extend  ventrad 
forming  the  ridges  which  separate  the  disc  into  fosscttes.  These  ridges 
are  composed  of  fibrous  connective  tissue  in  which  a  few  nuclei  are 
embedded. 


52  ILLIXOIS  BIOLOGICAL  MOSOGRAPHS  [332 

Alimentary  Tract. — The  moutli  funnel  is  a  cup  shaped  muscular 
structure  (Fig.  51)  which  functions  as  an  organ  of  adhesion.  There 
is  no  oral  sucker.  The  mouth  funnel  is  O.OS  to  0.1  mm.  in  diameter, 
sub-terminal  in  position.  There  is  no  prepharynx,  the  mouth  funnel 
opens  directly  into  the  pharynx.  The  latter  is  a  spherical  muscular 
organ  0.09  to  0.1  mm.  in  diameter.  As  described  by  Osborn  for  C. 
insignis,  it  is  followed  by  a  very  short  esophagus,  which  in  the  anterior 
part  has  a  cuticidar  lining  and  in  the  posterior  part  where  tlie  esopha- 
gus passes  over  into  the  intestine,  a  lining  of  flattened  epithelial  cells. 
The  intestine  is  an  elongate  sac  or  tube  extending  on  the  dorsal  side 
of  the  body  0.1  to  0.2  mm.  posterior  to  the  caudal  edge  of  the  testis. 
It  varies  but  slightly  in  caliber,  averaging  about  0.075  mm.  in  diameter. 
The  wall  consists  of  a  fibro-membranous  sheet  upon  which  rests  a  layer 
of  columnar  epithelial  cells.  The  large  deeply  staining  nuclei  of  the 
epithelial  cells  lie  in  the  basal  part  while  many  delicate  elongate  proc- 
esses extend  out  into  the  lumen  of  the  canal. 

Male  Reproductive  Organs. — The  testis  is  large,  single,  median,  its 
anterior  margin  lying  at  the  center  of  the  adhesive  disc.  It  is  almost 
spherical  and  measures  0.25  to  0.35  mm.  in  diameter.  Cells  of  various 
sizes  and  with  the  chromatin  material  in  various  stages  of  division,  as 
well  as  mature  spermatozoa  are  to  be  seen  in  sections.  Tlie  sperm  duct 
arises  at  the  anterior  part  of  the  testis  and  turns  to  the  left,  entering 
the  side  of  a  long,  much-coiled  seminal  vesicle  (Fig.  48").  This  vesicle 
is  a  large  tube,  0.1  to  0.175  mm.  in  diameter,  extending  from  the  region 
of  the  testis  to  the  cirrus  sac.  It  is  coiled  eight  to  sixteen  times  and  in 
all  mature  specimens  is  filled  with  spermatozoa.  Terminally  it  is  con- 
stricted into  a  small  tube  which  enters  the  large  cirrus  sac.  This  latter 
structure  (Fig.  53)  is  0.145  to  0.2  mm.  wide  and  0.2  to  0.25  mm.  long, 
has  a  strong  muscular  wall,  and  is  pyriform  in  shape,  the  smaller  end 
opening  anteriorly  at  the  genital  pore.  Inside  the  cirrus  sac  there  is 
a  dilated,  curved  portion  of  the  duct  which  has  muscular  avails  and  is 
lined  with  epithelial  cells.  Surrounding  the  duct  and  filling  the  cirrus 
sac  are  the  large  cells  of  the  prostate  gland.  These  are  pyriform  and 
average  26jli  long  by  17/x  wide.  In  living  specimens  the  cirrus  was 
observed  in  the  extruded  condition. 

Female  Reproductive  Organs. — The  ovary  is  a  small  organ,  ovoid 
in  shape,  averaging  0.16  mm.  in  length,  0.1  mm.  in  width,  and  0.05  mm. 
in  thickness.  It  is  located  (Figs.  46,  52)  at  the  right  of  the  median 
line,  slightly  anterior  to  the  middle  of  the  body.  The  oviduct  arises 
(Fig.  48)  at  the  posterior  ventral  margin  of  the  ovai'y  and  passes 
posteriad;  receives  a  short  common  vitelline  duct,  and  then  expands 
into  two  or  three  irregular  enlargements.    Mehlis'  gland  is  present,  the 


333]  XORTH  AMERICAS  ASPIDOCASTRIDAE—STrXKARD  53 

nuclei  lying  in  the  parenchyma  around  the  ootype.  The  uterus  passes 
posteriad  on  the  lateral  side  of  the  collecting  duct  of  the  excretory 
system  as  far  as  the  caudal  end  of  the  testis  where  it  turns  to  the  median 
line.  It  passes  ventrad  and  anteriad  beneath  the  testis ;  in  fi'ont  of  the 
testis  it  turns  dorsad  and  toward  the  ovarj',  but  just  before  reaching 
the  ovary  it  turns  and  crosses  to  the  opposite  side  of  the  body  and  then 
passes  with  little  deviation  to  the  genital  pore.  There  is  a  strong  sphinc- 
ter at  the  distal  end  of  the  uterus  (Fig.  54).  Eggs  were  present  at 
various  places  in  the  course  of  the  uterus  and  when  the  worms  were 
placed  in  tap  water,  the  eggs  near  the  pore  were  extruded.  The  eggs 
are  few  in  number,  not  more  than  six  being  present  in  any  specimen. 
They  vary  from  0.071  to  0.086  mm.  in  width  and  from  0.137  to  0.14") 
mm.  in  length.     The  average  of  twenty-five  is  0.075  by  0.141  mm. 

The  vitellaria  (Figs.  46,  49)  are  arranged  along  the  sides  of  the 
body,  extending  from  the  posterior  end  to  the  level  of  the  cirrus  sac. 
The  follicles  are  more  numerous  and  closer  together  in  the  posterior 
region,  gradually  becoming  fewer  in  the  anterior  part  of  the  vitelline 
zone.  They  lie  just  above  the  limiting  membrane  which  forms  the 
dorsal  boundary  of  the  musculature  of  the  adhesive  disc,  and  number 
up  to  forty  on  each  side.  They  vary  in  size,  measuring  from  10  to  40/x 
in  diameter.  In  some  specimens  they  appear  to  be  arranged  in  a  double 
row  on  each  side  with  the  follicles  placed  alternately,  but  there  is  com- 
mon and  wide  variation  from  this  condition.  Collecting  ducts  extend 
along  the  median  face  of  the  vitellaria  and  at  the  level  of  the  ootype 
pass  mediad  where  they  unite  to  form  a  small  receptacle  which  empties 
into  the  ootype.  In  C.  cokeri  the  vitelline  follicles  are  smaller  and  fewer 
in  number  than  in  C.  insignis. 

The  genital  pore  (Fig.  54)  is  double,  situated  in  the  median  line 
on  the  ventral  side  of  the  forebody,  dorsal  and  anterior  to  the  adhesive 
disc.  There  is  no  genital  atrium,  the  two  diiets  open  to  the  exterior 
separately,  the  opening  of  the  cirrus  sac  is  on  the  right  and  that  of  the 
metraterm  is  on  the  left.  Barker  and  Parsons  described  a  genital  atrium 
opening  thru  a  common  pore,  but  I  fail  to  find  such  a  structure.  In 
C.  insignis,  Osborn  described  a  single  genital  opening  and  a  genital 
atrium,  but  in  sections  of  C.  insignis  I  find  the  same  condition  as  in 
C.  cokeri. 

Excretory  Sysicm-. — ilost  of  the  observations  on  this  system  were 
made  on  living  specimens.  As  the  water  evaporated  from  under  the 
coverglass  the  worm  was  flattened  and  the  larger  excretory  tubules 
could  be  easily  followed.  The  pore  (Fig.  50)  is  median,  dorsal,  near 
the  posterior  end  of  the  body.  There  may  or  may  not  be  a  small  papilla- 
like prominence  around  the  pore.     There  is  a  single  excretory  vesicle, 


54  ILLINOIS  BIOLOGICAL  MOSOCRAPHS  [334 

situated  between  tlie  large  flask  like  ends  of  the  collecting  ducts  and 
the  pore.  In  the  pulsations  of  this  organ,  the  anterior  ventral  part 
contracted  and  the  constriction  passed  posteriad  and  dorsad,  expelling  the 
fluid  thru  the  pore.  The  two  collecting  ducts  extend  cephalad  from  the 
excretory  vesicle,  one  on  either  side  of  the  forebody,  median  to  the  vitel- 
laria.  Just  posterior  to  the  pharynx  each  duct  divides,  sending  a  brancli 
cephalad  on  the  lateral  side  of  the  pharynx  and  anterior  sucker,  and  a 
second  branch  turns  caudad.  This  caudal  branch  subdivides  into  a 
branch  leading  to  the  region  of  the  genital  pore,  and  a  longer  larger 
branch  which  passes  posteriorly  to  the  region  of  the  testis  and  receives 
many  smaller  side  branches.  Cross  sections  (Fig.  49)  show  the  collect- 
ing ducts  to  be  dorsal  in  position.  In  morphological  and  histological 
features  the  excretory  system  of  C.  cokeri  is  similar  to  that  of  C.  insig- 
nis.  Osborn  gives  a  comparison  of  the  excretory  sj^stem  in  that  species 
with  the  same  system  in  other  genera  of  the  family. 

Sensory  Structures. — There  is  a  dorsal  nerve  commissure  crossing 
the  anterior  part  of  the  pharynx,  and  nerves  were  traced  running  ceph- 
alad and  caudad  from  it.  In  about  half  of  the  specimens  mounted  in 
toto,  a  pair  of  black  pigment  spots  is  present  on  the  dorsal  commissure. 
In  others  only  a  single  spot  is  visible  and  in  a  few  specimens  none  could 
be  found.  In  all  the  sectioned  worms,  however,  both  "ej'e  spots"  were 
observed,  altho  in  some  they  were  very  small  and  diiBcult  to  find.  These 
structures  are  dorsal  and  anterior  to  the  pharynx  (Fig.  58)  and  consist 
of  a  large  number  of  black  pigment  granules.  No  lens  is  present. 
Barker  and  Parsons  report  that  eye  spots  were  not  found. 

At  the  ends  of  the  cross  partitions  of  the  adhesive  disc  are  the  mar- 
ginal organs  (Fig.  55).  These  structures  occur  in  the  interstices  be- 
tween the  muscular  ridges  of  the  ventral  disc  and  its  perijiheral  wall. 
Such  an  organ  consists  of  a  fine  tube  about  20;n  in  length  and  l/x  in  di- 
ameter, leading  dorsad  from  the  ventral  surface  of  the  ridge  and  termi- 
nating in  a  large  spherical  cavity  in  the  form  of  a  bulb.  The  entire  or- 
gan is  lined  with  cuticula,  continuous  with  that  of  the  external  surface 
of  tlie  body.  The  external  half  of  tlie  canal  possesses  a  thick  wall  com- 
posed of  annular  muscles,  while  the  internal  portion  has  a  thin  wall  with 
a  few  anni;lar  fibers  and  is  often  curved  or  looped.  At  the  external  end 
of  the  inner  i^ortion  there  is  a  flask-like  enlargement  which  is  connected 
with  the  heavy  v.alled  region  by  a  short  constricted  portion  about  2,u  in 
length.  Longitudinal  fibers  pass  from  the  wall  of  the  distal  part  of  tlie 
canal  to  points  near  its  inner  end  or  to  the  wall  of  the  cavitj'.  This  lat- 
ter structure  is  spherical  or  oval  15  to  20jii  in  diameter,  and  empty  in 
most  of  the  sections.  It  has  a  fibro-membranous  wall  and  in  a  few  eases 
is  filled  with  homogenous  granular  substance  or  fluid.     In  other  sections 


335]  NORTH  AMERICAX  ASPIDOCASTRIDAE—STUXKARD  55 

the  bulb  contains  a  few  granules  or  "concretionary  bodies",  but  in  struc- 
ture these  appear  identical  with  the  cutieular  lining  of  the  cavit.y.  As 
mentioned  above  the  organs  are  located  in  the  angles  between  the  muscu- 
lar ridges  and  the  wall  of  the  disc,  and  are  set  in  a  mass  of  non-staining 
tibrous  connective  tissue.  Some  of  the  fibers  pass  dorsad  from  the  bulb 
between  the  muscular  ridges  to  the  limiting  membrane  of  the  disc,  but 
in  appearance  these  are  similar  to  the  others  and  there  is  nothing  to  in- 
dicate that  they  are  nervous  in  character.  However  in  one  section, 
stained  with  Heidenhain's  iron  haematoxylin,  there  is  a  nerve  fibril  pass- 
ing around  tlie  bulb  and  terminating  on  the  inner  end  of  the  heavy  walled 
portion  of  the  canal  (Fig.  55).  Other  nervous  structures  were  not  ob- 
served. The  connective  tissue  contains  many  nuclei,  similar  in  size  and 
shape,  and  in  no  ease  was  a  connection  bet\veen  these  nuclei  and  the 
marginal  organ  observed.  No  glandular  cells  and  no  evidence  of  a  se- 
cretion were  found.  In  the  studj^  of  living  specimens  it  was  noted  that 
tlie  marginal  organs  were  everted  and  retracted  as  the  worm  moved. 
Everted  they  appeared  as  membranous  sacs  and  their  movement  was 
rapid  and  precise.  No  evidence  was  found  to  indicate  that  these  organs 
l)0ssess  a  glandular  function ;  the  character  of  their  movement  and  the 
nerve  fibril  leading  to  tlie  canal  as  demonstrated  incline  the  writer  to  re- 
gard these  structures  as  sensory. 

Similar  organs  have  been  reported  as  present  in  all  the  genera  of 
the  family  except  Stiehocotyle.  They  were  first  noted  in  Aspidogaster 
by  Dujardin  (1845)  who  described  them  as  pores  or  orbicTilar  glands. 
Voeltzkow  (1888)  observed  in  Aspidogaster  that  they  were  protrusible 
and  retractile,  and  for  this  reason  decided  they  w'ere  sensory.  Monti- 
celli  (1892)  described  them  in  Cotylogastcr  michadis  and  supported  the 
idea  of  their  sensory  character.  Niekerson  (1902)  described  in  Cotylo- 
gastcr occid-entalis  a  bundle  of  fibers  which  he  regarded  as  a  nerve  en- 
tering the  bulb  at  its  basal  end,  and  a  cluster  of  bipolar  nei've  cells  lying 
upon  tlie  side  of  tlie  bulb  against  which  the  canal  is  coiled  when  retracted, 
lie  stated  that  the  presence  of  the  bipolar  cells  establishes  the  sensory 
character  of  tliese  organs.  He  described  the  bulb  as  filled  with  vesicular 
or  granular  material,  and  tho  no  nuclei  were  discernible,  regarded 
tliis  as  cytoplasm  of  granular  cells  in  different  stages  of  activity. 

Looss  (1902)  in  Lophotaspis  valid  described  two  types  of  structures 
as  occurring  in  the  interstices  between  the  muscular  ridges  of  the  ventral 
disc.  Those  around  the  peripherj'  of  the  disc  at  the  ends  of  the  cross 
ridges  he  called  "marginal  bodies"  and  those  at  the  intersections  of  the 
ridges  he  called  "tentacles."  The  first  he  compared  with  the  marginal 
organs  of  other  aspidogastrid  genera,  and  the  tentacles  differ  only  slightly 
in  details  of  structure.     He  stated  there  was  nothing  in  the  structure 


56  ILLIS'OIS  BIOLOGICAL  MOSOGRAPHS  [336 

of  the  marginal  bodies  to  warrant  tlie  former  belief  in  their  sensory 
character.  Granules  in  the  cavity  he  regarded  as  droplets  of  a  secretion ; 
and  in  the  connective  tissue  dorsal  to  the  cavity  he  described  sac-like 
spaces  with  fine  granular  contents,  and  he  found  also  nuclei  but  was  un- 
certain whether  they  lay  in  the  spaces  or  between  them.  The  marginal 
bodies  he  regarded  as  glandular  organs  altho  doubtful  as  to  their  exact 
function.  He  described  the  tentacles  as  having  a  spindle-shaped  cavity 
with  glandular  apparatus  around  the  inner  end,  and  a  canal  leading  from 
this  blind  end  to  the  limiting  membrane  which  formed  the  dorsal  wall  of 
the  musculature  of  the  adhesive  disc.  He  considered  these  structures  as 
adhesive  or  absorptive,  but  states  that  their  physiological  significance 
was  doubtful. 

Osborn  (1904)  in  C.  insignia  described  the  marginal  organs  as  con- 
sisting of  three  parts,  the  canal  with  its  muscular  wall,  the  cavity,  and  a 
dorsal  fibrous  part.  The  fibrous  part  he  regarded  "as  a  trunk  of  nerve 
fibers  running  at  least  to  the  muscles  of  the  organ  and  perhaps  partly 
sensory  as  well."  The  central  cavity  possessed  "a  lining  of  moderate 
thickness  composed  of  cuticle  outwardly  but  of  nucleated  epithelium  on 
the  inner  side. ' '  This  cavity  he  found  empty  or  with  one  or  more  ' '  con- 
cretionary ob.iects."  He  says,  "This  indicates  that  secretion  is  going  on 
the  products  being  removed  from  time  to  time.  I  think  the  muscles  de- 
scribed above  may  be  used  in  discharging  these  products,  the  longitudinal 
fibers  may  act  as  dilators  of  the  outlet,  needed  to  enable  such  large  ob- 
jects to  make  their  escape."  Later  he  states,  "I  do  not  find  in  Cotjdaspis 
any  evidence  of  a  glandular  structure  in  the  fibrous  part,  and  do  con- 
sider the  bulbous  part  as  epithelial  and  secretory. ' ' 

TJie  marginal  organs  apparently  differ  somewhat  in  structure  in 
the  different  genera.  Of  all  the  authors,  Looss  alone  seems  to  have 
morphological  evidence  for  his  conclusion  that  in  Lophotaspis  they  are 
glandular  in  character.  The  statement  of  Osborn  that  in  Cotylaspis 
insignis  the  bulb  is  partly  lined  with  cuticula  and  partly  with  secretive 
epithelium,  I  regard  as  doubtful.  Certainly  in  my  sections  of  that  spe- 
cies (Fig.  56)  the  bulb  is  lined  with  cuticula  thru  out.  In  the  dorsal  part 
of  the  cavity  shown  there  are  many  small  structures  but  they  appear  to 
be  composed  of  the  same  material  as  the  lining  cavit.y.  If  they  are  eutie- 
ular,  this  would  argue  against  the  glandular  character  of  the  organ  since 
in  its  functional  activity  the  material  would  be  swept  out  with  the  secre- 
tion instead  of  accumulating  and  forming  such  large  objects  as  he  .shows 
in  his  figure.  Furtliermore  it  would  be  almost  if  not  entirely  impossible 
for  such  large  bodies  to  pass  thru  the  small  canal  which  leads  to  the  ex- 
terior. These  "concretionary  objects"  are  apparently  the  only  basis 
for  Osborn 's  claim  that  the  organs  are  glandular  since  he  stated  that  he 


337]  NORTH  AMERICAS  ASPIDOGASTRIDAESTUSKARD  57 

found  no  glandular  structure  in  the  fibrous  part.  Instead  of  supporting 
I  believe  that  they  are  subversive  to  the  idea  of  the  glandular  nature  of 
th«  organ. 

In  my  material  the  fibers  which  pass  dorsad  from  the  bulb  are  iden- 
tical in  appearance  with  the  adjacent  connective  tissue  and  do  not  ap- 
pear to  be  nervous.  The  muscular  wall  of  the  canal  is  I  believe,  used 
primarily  in  the  eversion  and  retraction  of  the  external  part  of  the  canal. 
In  living  specimens  under  observation  the  everted  part  of  the  marginal 
organ  was  about  the  size  and  shape  of  the  thick-walled  distal  portion  of 
the  canal,  and  this  is  probably  the  only  part  protrusible.  With  tliis  ever- 
sion, the  base  of  the  thick  walletl  portion  to  which  the  nerve  is  distributed 
would  be  at  the  tip  of  the  everted  structure  in  a  position  to  function  in  a 
sensory  capacity. 

Comparisons. — This  is  the  third  aspidocotylean  described  from  tur- 
tles, the  two  previously  reported  forms  being  Cotylaspis  Icnoiri  Poirier 
1886,  and  Lophotaspis  vallci  Stossieh  1899,  both  African  species.  Poirier 
described  C.  Icnoiri  from  the  intestine  of  Tctrathijra  vaillanti  from  Sen- 
egal, and  Looss  (1902)  reports  it  as  occurring  also  mTrionyx  notiiica  of 
the  Nile.  Lophostaspis  vallci  is  parasitic  in  the  stomach  of  Thalassoclu  li/s 
corticata.  Cotylaspis  cokeri  is  very  diffei'eut  from  Lophotaspis,  but  shows 
considerable  resemblance  to  C.  Icnoiri.  However,  a  comparison  of  the 
description  of  C.  Icnoiri  with  specimens  of  C.  insignis  and  C.  colcri  shows 
decided  difference  in  the  size  and  shape  of  the  worms  and  of  the  adhesive 
disc,  in  the  number  of  alveoli  and  marginal  organs,  in  the  sive  of  ovary 
and  testis,  of  cirrus  sac,  and  of  eggs.  The  three  forms  agree  in  essential 
morphological  features  and  fit  the  diagnosis  of  the  genus  Cotylaspis  as 
given  by  Leidy,  but  are  equally  clearly  good  species  in  that  genus. 

CL.VSSIFIC.VTION  OF  THE  FAJIILT 

The  last  classification  of  tlie  Aspidogastridae  was  made  by  N'ickerson 
(1902).  Since  additions  and  changes  have  subsequently  been  made, 
further  revision  seems  advisable.  The  present  arrangement  is  largely 
based  on  the  work  of  Nickerson  and  brings  tlie  classification  to  date. 
Present  information  supports  the  validity  of  the  following  genera. 

I.  Aspidogaster  von  Baer  1827.  Type  species,  A.  conchicola  von 
Baer. 

Oval  adhesive  disc,  four  rows  of  alveoli,  marginal  organs  present, 
mouth  subterminal,  no  oral  sucker,  one  testis. 

This  genus  contains  A.  conchicola  which  infests  the  pericardium  and 
renal  organs  of  various  species  of  Unionidae  in  Europe  and  Xorth  Amer- 
ica. It  is  also  found  in  gastropods  and  in  the  immature  condition  in 
th«  intestine  of  Unionidae.  Other  species  of  this  genus  are  A.  limacoides 


58  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [338 

Diesing  1834  from  the  intestine  of  a  fish  (Leueiscus)  in  Eui'ope,  a  form 
which  Stafford  (1896)  and  Kofoid  (1899)  suspect  of  being  identical  mth 
A.  conchicola.  The  species  A.  macdonaldi  was  placed  in  this  genus  by 
Jlontieelli  (1892)  and  removed  to  Lophotaspis  by  Looss  (1902).  Linton 
(1905)  described  A.  ringens  from  the  intestine  of  Micropognon  undula- 
tus  and  Trachinotus  caroUnus  at  Beaufort,  North  Carolina.  MacCallum 
and  MacCallum  (1913)  gave  a  more  complete  description  of  A.  ringens 
and  described  A.  kemostoma  n.  sp.,  both  from  the  intestine  of  Trachinotus 
carolinus. 

II.  Cotylaspis  Leidy  1857.      Type  species,  C.  insignis  Leidy. 
Oval  adhesive  disc,  three  rows  of  alveoli,  marginal  organs  present, 

mouth  subterminal,  no  oral  sucker,  one  testis. 

This  genus  contains  the  species  C.  insignis,  C.  Icnoiri,  and  C.  cokeri. 
C.  lenoiri  was  described  by  Poirier  (1886)  as  a  species  of  Aspidogaster. 
Monticelli  (1892)  created  a  new  genus  Platyaspis  to  contain  Poirier's 
species,  evidently  overlooking  the  similarity  between  it  and  the  form  re- 
ported by  Leidy.  He  declined  to  accept  the  genus  Cotylaspis,  suggesting 
that  C.  insignis  was  a  species  of  Aspidogaster.  Braun  (1879-1893)  as- 
cribed the  species  to  Aspidogaster.  Kofoid  (1899)  established  the  val- 
idity of  Leidy 's  genus  but  contended  that  the  genus  Platyaspis  should  be 
retained  for  Poirier's  species.  Nickerson  (1902)  argued  that  tlie  differ- 
ences between  the  African  and  American  species  are  not  of  generic  im- 
portance and  suppressed  the  genus  Platyaspis,  making  Aspidogaster 
lenoiri  Poirier  and  Platyaspis  lenoiri  (Poir.  1886)  Monticelli  1892,  syn- 
onomous  with  Cotglaspis  lenoiri  Poir.  Cotylaspis  insignis  occurs  ectopara- 
sitically  in  the  mantle  cavity  of  Unionidae  in  North  America;  C.  lenoiri 
is  from  the  intestine  of  Tetrathyra  vaillanti  of  Africa;  and  C.  cokeri  is 
from  the  intestine  of  Malacoclemys  Icsueurii  of  North  America. 

III.  Macraspis  Olsson  1868.  Type  species,  M.  elegans  Olsson. 

A  single  row  of  confluent  acetabula  in  adhesive  organ,  marginal  or- 
gans present,  moutli  terminal,  one  testis. 

The  single  species  is  parasitic  in  the  gall  bladder  of  Chiinaera  mon- 
strosa,  a  fish  from  the  coast  of  Europe. 

IV.  Stiehocotyle  Cunningham  188-4.  T.ype  species,  S.  nephropis 
Cunningliam. 

A  single  row  of  more  or  less  distinct  acetabula,  marginal  organs  lack- 
ing, mouth  subterminal,  oral  sucker  absent,  two  testes. 

Cunningham's  original  description  was  of  the  larva  and  Monticelli 
(1892)  declined  to  recognize  its  generic  importance,  thinking  it  might 
be  a  form  of  Macraspis.  Odhner  (1898)  by  discovering  the  adult  and 
tracing  the  life  history,  established  the  genus.  Adults  live  in  the  bile 
ducts  of  the  liver  of  rays ;  larvae  occur  encysted  in  the  wall  of  the  intes- 


i 


339]  XORTH  AMERICAX  ASPIDOGASTRIDAE—STUSKARD  59 

tine  of  the  larger  marine  Crustacea.  Cunningham  described  it  from  the 
Norwegian  lobster,  Nephrops,  and  Nickerson  (1895)  reported  it  from  the 
American  lobster,  Homants  americanus. 

V.  Cotj'logaster  Monticelli  1892.  Type  species,  C.  michaelis  Mon- 
ticeUi. 

Adhesive  disc  with  three  rows  of  alveoli,  marginal  organs  present, 
mouth  terminal,  oral  sucker  present,  two  testes. 

Two  species  have  been  described;  C.  michaelis  occurs  in  the  intestine 
of  Cantharits  vulgarus,  a  European  fish,  and  C.  occidentalis  Nickerson 
1899  is  parasitic  in  the  intestine  of  Aplodinotus  grunniens  of  North 
America. 

VI.  Lophotaspis  Looss  1902.  Type  species,  L.  vallei  (Stossich) 
1899. 

Adhesive  organ  with  four  rows  of  alveoli,  marginal  organs  present  at 
all  the  intersections  of  the  ridges  of  the  adhesive  disc,  cirrus  absent. 

Loos  in  1901  reported  L.  adhacrens  as  belonging  to  a  new  genus  of  the 
Aspidogastridae,  but  was  not  aware  that  Stossich  two  years  before  had 
described  the  same  form  as  Aspidogaster  vallei.  Looss  later  (1902)  de- 
scribed and  figured  the  form  under  the  name  of  Lophotaspis  vallei.  In  the 
same  paper  he  compared  A.  macdonalcU  with  L.  vallei  and  placed  the 
former  species  in  the  genus  Lophotaspis.  This  trematode  was  reported 
but  not  named  by  Macdonald  in  1878,  and  named  by  MonticeUi  (1892) 
as  a  species  of  Aspidogaster.  Nickerson  (1902)  declared  it  to  be  an  as- 
pidogastrid,  but  different  from  aU  other  known  species,  and  predicted  that 
a  new  genus  would  have  to  be  erected  for  it  when  its  structure  was  better 
known.  Macdonald  reported  one  hundred  eighty  extensile  structures, 
like  the  tentacles  of  a  snail,  occurring  at  the  margins  and  intersections 
of  the  ridges  of  the  adhesive  disc.  Nothing  is  known  of  the  internal 
structure.  Looss  in  placing  the  form  in  the  genus  Lophotaspis  stated : 
"Mit  ihrer  tentakeltragenden  Bauchscheibe  bildet  die  Art  aber  ganz 
zweifellos  einen  fremden  Eindringling  in  der  Gattuug  Aspidogaster,  da 
dessen  t\-pisehen  Art  jedenfalls  solche  Tentakel  nicht  besitzt.  Gerade 
diesen  auffallended  Character  aber  teilt  sie  mit  Lophotaspis;  bin  ich 
geneigt,  A.  macdonaldi  Monticelli,  trotzdem  bei  ihm  die  Geuitaloffnung 
weiter  riickwarts  Liegt  als  bei  Lophotaspis  vallei,  aus  dem  genus  Aspido- 
gaster herauszunehmen  and  zu  Lophotaspis  zu  stellen." 


60  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [340 


PARAMPHISTOMIDAE 

HISTORICAL  REVIEW  OF  THE  FAMILY 

The  genus  Amphistoma  was  created  by  Rudolphi  (1801)  ;  coneerniug 
it  Stiles  and  Hassall  (1908)  state,  "Rudolphi  deliberately  renamed  a 
previously  validly  named  genus,  namely  Strigea  Abildgaard,  1790,  re- 
ferring clearly  tothis  fact  both  in  1801a,  50-51,  and  1802b,  92.  He  makes 
but  one  combination  {AmpMstoma  suhclavatum),  but  since  Amphistoma 
is  clearly  a  new  name  proposed  for  an  older  one  (Strigea),  which  Rud. 
changed  on  the  alleged  ground  that  it  was  inappropriate,  Amphistoma 
should  be  suppressed  in  favor  of  Strigea  and  take  the  same  species  as 
type." 

Fischoeder  (1903)  stated:  "In  Bezug  auf  den  Namen  Amphisto- 
mum  will  ich  jedoch,  wie  schon  gesehen  (1901),  nochmals  darauf  hiu- 
weisen,  dass  der  Name  Amphistoma  von  Rudolphi  (1801)  als  neue 
Bezeichniing  fiir  die  Gattung  Strigea  Abildg.  1790  eingefiihrtworden  ist. 
Der  Name  Amphistoma  kommt  daher  nach  dem  Prioritiitsgesetz  als 
synonjTn  zu  Strigea  in  Fortfall.  Die  ursprlingliche  einzige  und  also 
auch  typische  Art  der  Gattung  Strigea  Abildg.  1790  (Amphistoma  Rud. 
1801)  war  Plamiria  strigis  Goeze  1782  Amphistoma  macrocephalum,  Rud. 
1809  Holostomum  macrocephalum  Nitsch.  1819).  Wenn  daher  der  Name 
Strigea  wieder  zu  Geltung  viaeder  bebracht  werden  soil,  so  darf  er  nur 
fiir  die  heutige  Gattung  Holostomum  weitergefiihrt  werden,  wahrend 
die  heutige  Gattung  Amphistomum  einen  anderen  Namen  erhalten 
muss.  Ich  habe  in :  Zool.  Anz.  1900,  V.  24,  p.  367  den  Namen 
Paramphistomum  vorgeschlagen  vmd,  die  Eintheilung  nach  dem  Fehlen 
oder  Vorhandensein  der  Pharyngealtaschen  beibehaltend,  in  der  Fam. 
Paramphistomidae  Fischdr.  (Amphistomidae  Montic.  1888)  die  Unter- 
familien  Paramphistominae  und  Cladorchinae  Fischdr.  unterschieden. 
In  diesen  beiden  Unterfamilien  lassen  sich  die  bekannten  Formen  unter- 
bringen. ' '  The  names  Paramphistomum  and  Paraphistoraidae  have  been 
accepted  by  Liilie,  Looss,  Odhner,  and  other  writers  and  are  used  in  this 
paper. 

The  paramphistomes  of  mammals  were  the  first  forms  of  this  family 
discovered,  and  they  have  been  the  subjects  of  extensive  study  by  Fisch- 
oeder (1903)  and  Stiles  and  Goldberger  (1910)  ;  a  number  of  species  are 
known. 


341]        XORTH  AMERICAX  PARAMPHISTOMIDAE—STUNKARD  61 

I  have  beeu  unable  to  find  any  record  of  work  done  on  the  param- 
phistomes  of  fish  between  that  of  Diesing  (1836)  and  MaeCallum  (1905). 
Daday  (1907)  described  two  species  of  Diplodiscus,  two  species  of  a  new 
genus  he  called  Microrchis,  three  species  of  a  new  genus  named  Pseudo- 
eladorehis,  and  added  Amphistoma  oxycephalus  Dies,  with  two  new 
species  to  the  genus  Chiorchis.  He  included  a  section  on  the  anatomj'- 
and  histology  of  the  forms. 

The  only  paramphistomes  from  amphibians  are  four  species  of  Dip- 
lodiscus reported  from  frogs :  D.  subclavatus  from  the  frogs  of  Europe, 
D.  teniperatus  from  those  of  North  America,  and  D.  megalochriis  and 
D.  microchrus  from  Australian  frogs. 

Information  concerning  paramphistomes  of  reptiles  is  very  scanty. 
Brauu  (1901)  lists  three  species  from  turtles:  Amphistoma  grande  Dies- 
ing, A.  scleroporum  Creplin,  and  A.  sp.  Bellingham.  Bellingham  (1844) 
listed  Amphistoma  sp.  from  the  intestine  of  Chelonia  imhricata  but  gives 
no  description,  so  this  species  should  receive  no  further  consideration. 
Braun  (1901)  supplemented  the  description  of  Creplin  (1844)  by  a  brief 
report  of  the  single  specimen  of  A.  scleroporum  from  the  museum  at 
Greifswald,  but  the  worm  was  sexually  immature  and  consequently 
the  observations  were  limited.  A.  grande  was  collected  by  Natterer 
from  the  intestine  of  five  species  of  turtles  in  Brazil,  but  the  descrip- 
tion of  Diesing  is  confined  to  the  external  appearance  and  the  material 
may  have  comprised  more  than  one  species.  One  other  species  is  known 
from  turtles,  a  form  described  by  Looss  (1902)  as  A.  spinulosum  from 
the  intestine  of  Chcloiie  mydus.  The  description  of  Looss  is  very  com- 
plete but  because  of  the  scarcity  of  known  species  and  our  limited  knowl- 
edge of  the  group,  at  that  time  he  refrained  from  any  attempt  at  classi- 
fication. He  stated  that  the  species  is  probably  closely  related  to  A. 
scleroporum  and  A.  grande. 

In  addition  to  the  description  of  the  species,  Looss  (1902)  discussed 
the  question  of  the  oral  sucker  and  the  pharynx  in  the  group  and  com- 
piling evidence  from  compai'ative  anatomy  and  embryologj',  he  argued 
that  the  anterior  sucker  of  the  amphistomes  should  be  regarded  as  homolo- 
gus  to  the  oral  sucker  of  the  distomes.  In  this  paper  also  he  described 
the  muscular  thickening  at  the  caudal  end  of  the  esophagus  as  a  pharynx 
and  described  a  peristaltic  contraction  of  the  organ  from  the  anterior 
to  the  posterior  end,  altho  in  an  earlier  paper  (1896)  he  had  stated  that 
the  esophageal  thickening  of  Gastrodiscus  was  not  a  true  muscular 
pharynx.  Concerning  this  latter  structure,  Odhner  (1911)  says,  "Ich 
verwende  diese  Bezeichnung,  weil  es  mir  doch  nicht  so  ganz  sicher 
erscheint,  dass  es  sich  hier  um  ein  dem  gewohnlichen  Distomenpharynx 
liomologes  Organ  handelt.    Auch  wenn  es  so  wiire,  konnte  iibrigeus  der 


62  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [342 

ziemlieh  versehiedeue  Bau  eineu  besondei'n  Namen  rechtf ertigen ;  der 
Oesophagus  miisste  aber  dann  konseqnenterweise  als  Prapharynx 
bezeichnet  werden."  In  his  later  paper  Looss  (1912)  referred  to  this 
organ  as  an  esophageal  bi;lb. 

The  arrangement  of  the  fibers  in  concentric  lamellae  and  the  func- 
tion of  the  organ,  acting  as  sphincter  instead  of  a  dilating  pumping  or- 
gan, argue  against  its  homology  with  the  pharynx  of  the  distomes.  These 
conditions  I  found  myself  in  the  two  species  of  the  new  genus  Alasso- 
stoma.  However  in  the  other  of  my  new  forms,  Zygocotyle  ceratosa,  in 
stead  of  concentric  muscle  lamellae,  the  fibers  at  the  sides  of  the  lumen 
extend  radially.  A  thickening  of  the  esophageal  musculature  is  de- 
scribed for  Gastrodiscus,  Homalogaster,  Diplodiseus,  Microrchis,  Chior- 
chis,  Sehizamphistoma,  Alassostoma,  and  Zygocotyle.  In  agreement  with 
Looss  (1912),  the  writer  regards  the  tube  leading  from  the  oral  sucker 
to  the  intestine  at  the  esophagus  and  the  muscular  thickening  of  the 
wall  of  the  esophagus  as  an  esophageal  b\ilb. 

In  this  same  paper  Looss  (1912)  reinvestigated  the  species  Amphis- 
toma  sclcroporum  and  described  its  structure  in  detail.  Discussing  the 
taxonomy  of  the  species  he  says,  "Die  Frage  nach  den  Verwandtschaft- 
lichen  Bezeichnungen  des  Amp.  sclcroporum  ist  insofern  leicht  beant- 
wortet,  als  seine  enge  Verwandtsehaft  zu  A.  spinulosum,  auf  die  ich 
schon  friiher  vermutungsweise  hinwies  (1902b,  p.  437)  jetzt  offen  zutage 
tritt.  Ich  wiirde  nicht  zogern,  beide  Arten  in  dieselbe  Gattung  ein- 
zvu'eihen,  wenn  nicht  gewisse,  wenn  auch  kleine  Diiferenzen  im  anatom- 
iseheu  Baue  existierten  die  meiner  Auffassung  nach  innerhalb  von  wirk- 
lich  natiirlichen  Gattungen  nicht  vorkommeu.  Diese  Differenzen  bes- 
tehen,  1.  in  dem  Fehlen  des  vor  dem  Muudsaugnapfe  gelegenden  starken 
Sphincters  von  A.  sclcroporum  bei  A.  spinulosum;  2.  der  Reduction  der 
Saugnapftaschen,  die  bei  A.  spinulosum  deutlich,  bei  A.  sclcroporum 
nicht  nach  aussen  hervortreten ;  3.  dem  Fehlen  der  kleinen  Seitenzweige 
an  den  vordersten  Enden  der  Blasenschenkel  von  A.  sclcroporum  bei 
A.  spinulosum;  4.  in  dem  etwas  abweichenden  Bau  der  Dotterstocke  (bei 
A.  sclcroporum  in  der  Mitte  fast  zusammen  and  ohne  eigentliche  quere 
Dottergange,  bei  A.  spinulosum  rein  seitlicli  mit  langen  queren  Dottei'- 
gangen)  ;  5.  in  dem  etwas  verschiedenen  Verbal  ten  der  Lymphsehliiuche 
(ungemein  reiche  Verzweigung  im  Umkreise  der  SaugnJipfe  bei  A. 
sclcroporum,  kaum  angedeutete  Verzweigung  bei  A.  spinulosum).  Bin 
ich  demnach  aiif  Grunde  dieser  Unterschiede  auch  iiberzeugt,  dass  in  den 
beiden  Arten  Repriisentanten  je  eines  besondern  Genus  vorliegen,  so 
geniigt  fiir  meinen  gegenwartigen  Zweck  doch  die  formelle  Aufstelluug 
der  Gattung  Schizamphistomum  fiir  A.  sclcroporum,  in  die  ich  A.  spinu- 
losum  vorliiufig  provisorisch  einbeziehe.      Als  die  wesentlichen  Charak- 


343]        XORTH  AMERICAN  PARAMPHISTOMIDAE—STVXKARD  63 

tere  dieser  Gattung  oder  der  Unterfamilie,  zu  der  sie  sich  friiher  oder 
spiiter  auswachsen  wird,  betraclitet  ieli  deu  Avifbaii  der  Excretioublase 
aiis  zwei  sehr  langeu,  bis  ins  Ko])i'ende  einfaclien,  uuter  sieli  nicht  ver- 
bundenen  Schenkeln  und  den  Aufbau  des  Lymphgefasssj'stemes  aus 
jederseits  drei  in  der  Umgebung  der  Saugnapfe  verastelten  Sehlauchen." 

He  might  ■prell  have  added  to  his  list  of  differences  that  in  S.  spin  u- 
losum  there  is  a  single  loop  of  the  excretory  vesicle  wound  dorsally 
over  the  cecum  of  each  side  while  in  S.  scleroporum  there  are  eight  loops 
winding  irregularly  around  the  cecum  of  each  side.  In  the  same  article 
(p.  355)  speaking  of  the  excretory  system  in  paramphistomes  of  mammals 
he  says  this  system  is  situated  deep  in  the  body  and  in  the  larger  groups 
is  a  stable  and  conservative  organsystem.  In  a  former  paper  Looss 
(1902  :837)  says,  "Zwischen  der  Species  einer  natiirlicheu  Gattung 
bestehen  anatomische  Unterschiede  nicht;  die  Speeiescharaktere  werden 
dargestellt  allein  durch  Differenzen  in  der  Grosse  des  Korpers  und  der 
einzelnen  Organe,  Hand  in  Hand  mit  denen  leichte  Veranderungen  ihrer 
Form,  ihrer  Lage  und  wenn  sie  reicher  gegliedert  oder  in  eine  Anzahl 
von  Theilstiicken  zerfallen  sind,  Aenderungen  in  der  Zahl  der  Glieder 
resp.  der  Theilstiicke  geheu  konneu."  As  a  matter  of  fact,  the  argument 
of  Looss  in  my  opinion  appears  to  show  clearly  that  S.  sclcropormn  and 
S.  spinulosum  are  not  members  of  the  same  genus;  as  indeed  he  has  al- 
ready suggested  himself  that  in  future  researches  a  new  genus  will  have 
to  be  created  to  contain  S.  spinulosmn. 

The  single  paramphistome  reported  from  snakes  was  described  _^by 
Cohn  (1903)  as  Amphistomum  dolichocotyle,  and  in  his  (1904)  classifi- 
cation of  the  Diplodiscinae  placed  in  the  genus  Catadiscus.  It  is  from 
the  intestine  of  Herpetodrijas  fiiscus. 

The  only  paramphistomes  previously  known  from  North  America 
are  Amphistoma  grande,  reported  by  Leidy  (1SS8)  from  the  intestine  of 
the  terrapin ;  two  specimens  from  the  small  intestine  of  the  muskrat 
which  according  to  the  same  author,  "appear  to  belong  to  Amphistoma 
subtriquetrum" ;  Diplodiscus  tempcratus  Stafford  long  considered  iden- 
tical with  D.  suhclavatus  Dies.;  and  Wardius  zibetlilcus  Barker  and 
East,  from  the  cecum  of  Fiber  zibethicus.  The  reports  of  Leidy  contain 
no  description  except  the  length  of  the  worms.  Barker  and  East  suspect 
that  Leidy 's  specimens  from  the  muskrat  belong  to  their  new  genus  and 
species  Wardius  zibethicus;  and  it  is  not  unlikely  that  the  specimens  from 
the  terrapin  are  specifically  identical  with  those  described  here  as  Alasso- 
stoma  magnum  Stvuikard  1916.  Neither  the  description  of  Stafford 
nor  that  of  Barker  and  East  contains  complete  anatomical  information. 
Stafford  distinguished  between  the  lymph  and  excretory  sj'stems. 
Barker    and    East    make    no    mention    of    tlie    lymph    system ;    they 


64  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [344 

state  that  the  oral  sucker  is  wanting  and  describe  the  anterior  suclier  as 
the  pharynx,  notwithstanding  the  arguments  of  Pratt  (1900),  Looss 
(1902)  and  Stiles  and  Goldberger  (1910)  that  the  anterior  sucker  of  the 
amphistomes  is  homologous  with  the  oral  sucker  of  the  distomes. 

The  material  of  this  family  available  for  the  present  study  consisted 
of  representatives  of  two  species  from  North  American  turtles,  and  an- 
other species  from  the  duck,  Anas  platijrhyncJws.  A  study  of  the  liter- 
ature showed  that  these  forms  could  not  be  included  in  any  previously 
described  genera. 

THE  GENUS  ALASSOSTOMA 

A  new  genus  Alassostoma  is  formed  to  include  the  two  species  from 
turtles.  The  genus  is  characterized  by  the  presence  of  large  oral  evag- 
inations  which  open  independently  into  the  oral  sucker,  an  esophageal 
bulb  composed  of  concentric  muscle  lamellae,  a  hermaphroditic  duct, 
germ  glands  near  the  middle  of  the  body  in  the  median  line,  both  testes 
anterior  to  the  ovary,  vitellaria  consisting  of  small  scattered  follicles  in 
the  lateral,  and  posteriorly  in  median  areas  of  the  body,  Laurer's  canal 
opening  in  the  mid-dorsal  line  anterior  to  the  opening  of  the  excretory 
vesicle.  Alassostoma  magnum  is  to  be  taken  as  type  of  the  genus,  and 
in  it  is  included  also  the  new  species  A.  parvum. 

The  genus  Alassostoma  has  the  type  of  lymph  and  excretory  systems 
present  in  the  geniis  Schizamphistoma  and  designated  by  Looss  as  char- 
acteristic of  the  subfamily  to  which  that  genus  belongs.  Looss  (1912) 
predicted  that  with  the  discovery  of  other  forms  it  would  be  necessary 
to  create  a  new  subfamily  to  contain  them,  and  at  that  time  stated  the 
subfamily  characters.  With  the  discovery  of  a  second  genus,  so  similar 
to  Schizamphistoma  that  the  two  must  be  included  in  the  same  subfamily, 
the  formal  recognition  of  the  new  subfamily  is  necessar.y.  Schizamphis- 
toma Looss  was  designated  as  type  and  the  name  of  the  subfamily  be- 
comes Schizamphistominae.  The  subfamily  contains  the  genera  Schiz- 
amphistoma, including  also  8.  spinulosum  which  as  already  indicated  by 
Looss  and  discussed  in  this  paper  is  type  of  a  new  genus,  and  the  genus 
Alassostoma.  The  distinguishing  characters  of  the  subfamily  as  stated 
by  Looss  are  two  long  excretory  vesicles  which  extend  singly  to  the  an- 
terior end  of  the  body  and  a  lymph  system  composed  of  three  canals  on 
either  side  of  the  body  Avhich  run  longitudinally  and  break  up  into  many 
sinuses  in  the  regions  of  the  suckers. 

Comparisons. — When  one  compares  the  species  A.  magnum  and  A. 
parvum  with  descriptions  in  the  literature,  they  are  seen  to  agree  most 
closely  with  Schizamphistomum  scleroporum  and  S.  spinulosum  Looss. 


345]        XORTH  AMERICAS  PARAMPHISTOMIDAE—STUNKARD  65 

Mention  has  previously  been  made  of  the  anatomical  differences  existing 
between  these  species  and  a  statement  ventured  that  such  wide  and  fun- 
damental differences  should  not  be  present  in  a  natural  genus.  A.  mag- 
num agrees  with  S.  schroporum  in  general  appearance  and  size,  in  type 
of  excretory  and  lymph  systems,  character  of  vitellaria,  and  in 
general  tj-pe  of  reproductive  and  alimentary  organs;  but  A.  mag- 
num has  large  oral  evaginations,  which  pockets  are  reduced  and  do  not 
extend  outside  the  sucker  in  S.  scleroporum,  and  A.  magnum  lacks  the 
preoral  sphincter  which  is  present  in  S.  scleroporum.  In  A.  magnum 
the  uterus  and  cirrus  sac  open  to  the  surface  thru  a  common  hermaphro- 
ditic duct;  in  S.  scleroporum  thej-  open  separatelj-.  Looss  (1899  :551) 
says  one  of  the  most  important  of  generic  characters  is  the  structure  of 
the  copulatory  organs.  In  A.  magnum  the  testes  are  further  posteriad 
and  the  ovarj-  is  situated  one-fourth  to  one-third  of  the  body  length  from 
the  posterior  end  instead  of  at  the  level  of  the  anterior  margin  of  the 
acetabidum  as  is  the  case  in  S.  scleroporum.  In  S.  scleroporum  the  testes 
and  ovary  are  widely  separated  and  in  A.  magnum  they  are  compara- 
tively close  together.  These  differences  appear  to  be  of  sufficient  impor- 
tance to  exclude  the  American  species  from  the  genus  Schizamphistoma. 

A.  magnum  agrees  with  S.  spinulosum  in  the  presence  of  oral  evag- 
inations and  lack  of  preoral  sphincter,  but  differs  from  it  in  the  manner 
of  the  coiling  of  the  excretory  vesicles,  in  the  presence  of  a  common  lierm- 
aphroditie  duct  and  in  the  character  of  the  vitellaria,  as  well  as  the  rela- 
tive positions  of  the  testes  and  ovary.  The  morphological  facts  show 
differences  too  fundamental  to  permit  the  inclusion  of  both  these  species 
in  a  single  genus. 

Alassostoma  parvum  agrees  with  A.  magnum  in  general  morpho- 
logical features,  presence  of  oral  evaginations,,  lack  of  preoral 
sphincter,  type  of  lymph  and  secretorj'  systems,  character  of  geni- 
tal organs  and  ducts,  also  in  relative  position  of  testes  and  ovary.  A. 
parvum  therefore  agrees  with  and  differs  from  S.  scleroporum  and  S. 
spintdosum  in  the  same  manner  as  A.  m<ignum.  That  the  two  forms  are 
not  different  developmental  stages  of  the  same  species  is  showni  by  the 
great  difference  in  the  size  of  the  worms  and  the  relative  differences  in 
the  size  of  suckers  and  genital  organs.  One  of  the  species  of  A.  magnum 
10  mm.  long  is  not  sexually  mature,  while  in  the  sectioned  specimen  of  A. 
parvum  which  is  less  that  3  mm.  long  spermatoza  were  present  in  the  tes- 
tes and  vas  deferens.  Further,  ova  were  present  in  the  oviduct,  and  tlio 
ootypc  and  anterior  part  of  the  uterus  were  filled  with  spermatoza. 
Eggs  were  present  in  only  one  of  the  seven  specimens  of  A.  magnum  and 
the  absence  of  eggs  in  the  three  specimens  of  A.  parvum  does  not  signify 
that  it  is  a  young  stage  of  A.  magnum.     A.  magnum  is  large  and  has 


66  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [346 

small  Slickers  and  A.  parvtiin  is  small  and  has  relatively  large  suckers, 
and  this  feature  suggested  the  name  Alassostoma. 

ALASSOSTOMA  MAGNUM  Stunkard  1916 
[Figures  59  to  65] 

The  material  of  this  species  consists  of  one  worm  from  Pseudemys 
troosti  from  Havana,  Illinois ;  one  from  P.  elegans  from  the  same  locality ; 
two  from  P.  elegans  from  Chicago,  Illinois;  and  three  specimens  from  an 
unknown  turtle  from  Marshall,  Missouri.  The  first  four  specimens  were 
collected  by  the  writer  from  the  large  intestine  near  its  juncture  with 
the  small  intestine,  and  the  material  from  Marshall,  Mo., bears  the  label, 
"From  cloaca  of  turtle." 

In  the  preserved  state  the  worms  are  10  to  12  mm.  in  length,  3  to  5 
mm.  in  breadth,  and  1.5  to  2  mm.  in  thickness.  One  specimen  studied 
in  the  living  condition,  measured  18  mm.  in  length  when  fully  extended ; 
preserved  it  is  11  mm.  long,  3.8  mm.  wide  and  2  mm.  thick.  One  fixed 
specimen  10  mm.  long  and  3  mm.  wide  is  not  sexually  mature. 

In  the  living  state  the  worms  are  clear,  hyaline,  with  the  digestive 
eeca  visible  as  brown  lines.  Their  movements  are  very  slow.  In  shape 
(Fig.  59)  they  are  more  or  less  oval,  with  the  acetabulum  forming 
a  slight  caudal  projection.  The  acetabulum  is  slightly  sub-terminal,  cir- 
cular or  ovoid,  usually  wider  near  the  anterior  than  the  posterior  end. 
The  opening  is  necessarily  relatively  narrower  than  the  sucker  itself,  in 
one  specimen  the  opening  is  merely  a  slit,  1.4  mm.  long,  0.38  mm.  wide 
near  the  anterior  end  and  posteriorly  tapering  to  a  point.  In  the  largest 
specimens  the  acetabulum  is  2.5  mm.  long  by  2  mm.  wide,  and  in  the 
smallest  it  is  2  mm.  by  2  mm. 

The  cuticular  covering  of  the  body  is  unarmed,  and  measures  10  to 
12;u  in  thickness.  It  is  turned  in  at  the  openings  of  the  excretory  and 
reproductive  systems  and  lines  the  digestive  tract  to  the  bifurcation. 
The  dermo-muscular  wall  has  the  circular,  longitudinal,  and  oblique  layers 
well  developed  and  inside  the  oblique  layer  there  is  an  additional  layer 
of  longitudinal  fibers  (Fig.  60).  Dorso-ventral  fibers  are  scanty  or 
lacking  and  the  parenchyma  of  the  bodv  is  very  loose  and  vacuolated 
(Fig.  64). 

Alimentary  tract. — The  oral  sucker  is  terminal,  spherical  to  ovoid 
in  shape,  usually  longer  in  the  antero-posterior  axis  and  somewhat  wider 
anteriorly  than  posteriorly.  It  is  deeply  set  in  the  parenchyma  of  the 
body  and  measures  0.9  to  1.35  mm.  in  length  and  0.6  to  0.9  mm.  in  width. 
Radial  fibers  pass  from  the  external  limiting  membrane  to  the  cuticula 
lining  the  sucker;  in  a  cross  section  thru  the  sucker  (Fig.  65),  the  inside 


347]        NORTH  AMERICAN  PARAMPHISTOMIDAE—STUNKARD  67 

two-thirds  of  the  outer  half  is  a  nuclear  zone  and  all  the  nuclei  are  col- 
lected in  this  area.  Half  way  between  the  nuclear  zone  and  the  lumen 
there  is  a  narrow  band  of  circular  fibers.  The  oral  evaginations  arise  at 
the  caudal  end  of  the  oral  sucker  by  two  separate  openings,  one  on  either 
side,  and  extend  dorsad  and  caudad.  They  are  0.35  to  0.6  mm.  long, 
flattened  dorso-veutrally,  0.15  to  0.2  mm.  in  width.  These  sacs  are  lined 
with  cuticula  and  their  wall  is  continuous  with  that  of  the  oral  sucker. 
Externally  there  is  a  layer  of  longitudinal  fibers  and  inside  this  sets  of 
annular  fibers  (Fig.  63).  Oblique  and  radial  fibers  are  occasionally  seen 
but  are  very  scanty. 

The  esophagus  is  0.6  to  1.3  mm.  in  length ;  it  is  lined  with  cuticula 
and  the  wall  contains  external  longitudinal  and  intei'iial  annular  fibers. 
At  the  caudal  end  of  the  esophagus,  just  anterior  to  the  bifurcation  of 
the  alimentary  tract,  there  is  a  prominent  esophageal  bulb.  It  varies 
from  0.65  to  0.95  mm.  in  lengtli  and  from  0.33  to  0.5  mm.  in  widtli ;  it 
is  formed  by  a  thickening  of  the  annular  fibers  of  the  wall  of  the  esoph- 
agus. A  cross  section  is  represented  in  Figure  60  and  shows  the  eighteen 
concentric  lamellae  of  muscles.  No  nuclei  are  present  in  these  annular 
muscles.  Both  the  oral  evagiuatious  and  the  esophagus  are  surrounded 
by  clusters  of  deeply  staining  cells  (Fig.  63).  Looss  (1S96)  described 
similar  cells  in  Gastrodiscus  and  believed  they  secrete  the  lining  of  the 
esophagus.  The  ceca  are  flattened  laterallj'  and  are  of  very  unequal 
caliber,  small  lateral  evagiuatious  occur  on  opposite  sides  at  the  same 
level  recalling  the  condition  in  some  of  the  Turbellaria.  The  diverticula 
extend  almost  to  the  acetablum,  about  0.37  mm.  intervening.  They  have 
a  muscular  coat  consisting  of  external  annular  and  internal  longitudinal 
fibers  and  an  epithelial  lining  of  columnar  cells  which  show  faint  long- 
itudinal striatious  (Fig.  62). 

Male  Reproductive  Organs. — The  testes  are  slightly  lobed,  oval, 
longer  in  the  transverse  diameter,  and  vary  in  size  from  0.27  by  0.35  mm. 
to  0.45  by  0.9  mm.  They  are  situated  one  behind  the  other  or  in  con- 
tracted specimens  slightly  on  opposite  sides  of  the  median  line.  They 
are  approximately  the  same  size  in  any  one  specimen  and  are  separated 
by  about  the  lengtli  of  one  of  the  testes,  tho  in  contracted  specimens  they 
may  lie  closer  together.  The  vasa  efferentia  arise  from  the  dorsal  anter- 
ior margins,  the  duct  from  the  posterior  testis  on  the  left  and  the  duct 
from  the  anterior  testis  on  the  right  side  of  the  body.  They  pass  dorsad 
and  cephalad,  and  0.4  to  0.5  mm.  caudad  of  the  bifurcation  of  the  diges- 
tive tract  they  unite  to  form  a  much  coiled  seminal  vesicle,  which  near 
the  pore  passes  into  a  small,  poorly  developed  cirrus  sac.  In  sectioned 
individuals  it  could  be  seen  that  the  seminal  vesicle  was  filled  witli  sper- 
matoza.     In  one  specimen  the  coils  of  the  vesicle  extend  thru  twenty 


68  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [348 

cross  sections  each  15/t  in  thickness,  and  the  tube  is  so  coiled  that  in  a 
section  of  the  worm  there  are  ten  or  fifteen  sections  of  the  vesicle.  In  an- 
other individual  cut  in  frontal  sections  the  seminal  vesicle  extends  antero- 
posteriorly  thru  0.57  mm.  The  prostate  gland  is  enclosed  by  the  cirrus 
sac  and  tills  the  entire  region  between  the  wall  and  the  central  canal. 
The  cells  are  more  numerous  in  the  posterior  part  of  the  sac,  gradually 
becoming  fewer  in  the  anterior  region.  The  sac  is  approximately  0.37 
mm.  long  and  0.185  mm.  in  diameter.  It  is  dorsal  on  the  right  side  of 
the  body,  and  the  terminal  end  of  the  utenis  is  ventral  on  the  left  side 
of  the  body. 

Female  Reproductive  Organs. — The  ovary  is  spherical  or  oval,  0.275 
to  0.35  mm.  in  length  and  0.33  to  0.57  mm.  in  width,  in  or  near  the  me- 
dian line,  about  the  width  of  the  caudal  testis  behind  the  latter.  The 
oviduct  is  very  small  and  arises  from  the  dorsal  margin  of  the  ovary  (Fig. 
61).  After  a  coil  posteriad  Laurer's  canal  is  given  off  and  passes  in  a 
winding  course  to  the  dorsal  surface.  There  is  no  I'eceptacnlum  seminis. 
Just  after  the  origin  of  Laurer's  canal,  the  oviduct  passes  into  Mehlis' 
gland,  where  the  vitelline  duct  is  received.  There  is  no  vitelline  re- 
ceptacle in  either  of  the  sectioned  worms,  but  the  right  and  left  diicts  are 
very  large.  They  meet  in  the  median  line  posterior  and  ventral  to 
Mehlis'  gland,  and  a  duct  passes  to  the  ootype.  The  uterus  coils  an- 
teriad,  either  between  or  around  the  testes  and  opens  thru  the  hermaphro- 
ditic duct  to  the  genital  pore. 

The  genital  pore  is  in  the  median  line  ventral  to  the  esophageal  bulb, 
and  there  is  a  small  genital  sinus.  The  cirrus  sac  and  metraterraal  por- 
tion of  the  uterus  open  to  the  exterior  thru  a  common  hermaphroditic 
duct  (Fig.  60). 

The  vitellaria  consist  of  small  irregularly  shaped  follicles,  lying  al- 
most entirely  in  the  ventral  half  of  the  body  and  extending  from  the  re- 
gion of  the  cephalic  testis  to  the  caudal  ends  of  the  ceca.  Anteriorly 
they  are  extracecal,  but  posteriorly  they  extend  into  the  intraeecal  area ; 
near  the  ends  of  the  ceca  about  half  of  the  follicles  are  between  the  di- 
verticula. 

Eggs  were  present  in  only  one  specimen.  Here  there  were  three ; 
they  measured  0.1  by  0.13  mm. 

Lymph  System. — This  'system  consists  of  three  canals  passing  long- 
itudinally on  either  side  of  the  body,  one  lateral  and  two  mesal  of  each 
cecum.  Of  the  median  pair,  one  is  dorsal  and  the  other  ventral  (Fig. 
59).  These  canals  are  not  straight  biit  wind  about  and  give  oft"  branches 
at  various  points.  These  branches  subdivide  in  turn  and  at  the  ends  the 
main  trunk  breaks  up  into  numerous  smaller  branches  so  that  the  entire 
body  is  penetrated  by  ramifications  of  this  system.     The  ceca,  the  genital 


349]        XORTH  AMERICAN  PARAMPHISTOMIDAE—STUXKARD  69 

orgaus,  and  the  suckers  are  especially  well  supplied  with  l.ympli  sinuses. 
Excretory  System. — The  excretory  pore  is  in  the  median  line  on  tlu; 
dorsal  surface,  near  the  posterior  end  of  the  body,  and  the  median  teriui- 
ual  vesicle  extends  interuallj-  and  anteriorly.  It  gives  off  a  brancli  to 
either  side  and  these  branches  of  the  collecting  vesicle  pass  auteriad, 
winding  about  the  cecum  of  either  side  in  many  loops  or  coils.  In  sections 
(Fig.  64)  the  tube  may  appear  on  either  side,  above,  or  below  the  cecum; 
in  a  single  section  it  may  be  cut  in  two  or  three  places  or  a  loop  may  piiss 
half  to  two-thirds  of  the  way  around  the  cecum.  No  connections  betw-.-en 
the  collecting  ducts  of  the  two  sides  could  be  seen,  and  they  were  traced 
to  the  region  of  the  oral  sucker. 

ALASSOSTOMA  PARVUM  Stunkard  1916 

[Figures  66  to  71] 

Three  individuals  of  this  species  were  collected  from  the  cloaca  of 
a  single  specimen  of  ChAydra  serpentina  from  Urbana,  Illinois.  One 
was  retained  as  an  alcoholic  specimen,  one  was  stained  and  mounted  as 
a  toto  preparation,  and  the  third  was  cut  into  cross  sections. 

The  worms  (Fig.  66)  are  thick  with  almost  parallel  sides,  rounded  at 
the  posterior  end  and  tapering  slightly  anteriorly.  Just  in  front  of  the 
acetabulum  the  body  narrows  sliglitly  and  then  widens  posteriorly  due 
to  the  presence  of  two  lateral  prominences  or  evaginations,  one  on  either 
side  at  the  level  of  the  anterior  part  of  the  acetabulum.  The  worms  are 
2.8  to  3  mm.  long  and  0.78  to  0.08  mm.  wide,  the  points  of  greatest  width 
are  at  the  level  of  the  testes  and  thru  the  posterior  lateral  prominences. 
The  sectioned  worm  is  0.8  mm.  in  width  and  0.54  mm.  in  thickness.  The 
acetabulum  is  subterminal,  oval,  0.8  mm.  in  length  and  0.7  mm.  in  width 
in  the  toto  preparation.  The  inside  measurements  of  the  same  sucker 
are  0.56  mm.  in  length  by  0.4  mm.  in  width  and  the  opening  is  0.45  mm. 
in  length  and  0.21  mm.  in  greatest  width. 

Alimentary  Tract. — The  oral  sucker  is  terminal,  ovoid,  0.46  ram. 
long  by  0.37  mm.  wide,  and  in  tlie  sectioned  worm  0.32  mm.  in  depth. 
In  the  mounted  specimen  tlie  sucker  is  widest  posteriorly,  and  from  the 
posterior  dorsal  part  on  either  side  there  is  an  oral  evagination.  These 
arise  separately  and  are  0.055  mm.  long.  Among  the  fibers  of  the  oral 
sucker  there  are  many  nuclei ;  they  are  situated  in  the  peripheral  half 
of  the  sucker  and  are  confined  to  the  central  two-thirds  of  the  external 
half.  There  are  also  among  the  nuiscle  fibers  glandular  cells  with  ducts 
to  the  lumen  of  the  sucker.  The  esophagus  is  somcMiiat  coiled  but  ex- 
tends thru  0.2  mm.  and  is  surrounded  by  large  deeply  staining  gland 
cells.  The  posterior  part  is  enlarged  by  the  thickening  of  the  annular 
muscles  of  the  wall  which  forms  the  esophageal  bulb  (Fig.  70).     This 


70  ILLI.XOIS  BIOLOGICAL  MOXOGRAPHS  [3S0 

structure  comprises  twelve  concentric  rings  or  lamellae  of  muscles.  It 
is  0.2  mm.  long  by  0.14  mm.  wide  in  the  toto  specimen  and  0.314  mm.  in 
depth  in  the  sectioned  individual.  The  diverticula  extend  posteriad  al- 
most to  the  cephalic  margin  of  the  acetabidum.  In  sections  they  are  oval, 
and  flattened  laterally.  In  the  intestine  of  the  sectioned  worm  there  are 
masses  of  small  nuclei,  possibly  from  tlie  epithelial  lining  of  the  cloaca 
of  the  host. 

Male  Reproductive  Organs. — The  testes  are  oval,  in  the  toto  speci- 
men they  are  0.17  mm.  long  bj^  0.17  mm.  wide,  and  in  the  sectioned  worm 
0.17  mm.  wide  by  0.29  mm.  thick.  They  are  situated  one  in  front  of  the 
other  in  the  median  line  and  in  the  ventral  part  of  the  body.  They  are 
close  together,  separated  only  by  a  thin  fibrous  slieet.  The  vasa  efferen- 
tia  arise  at  the  dorsal  margins  of  the  testes ;  the  duct  from  the  caudal 
testis  pas.s  anteriad  and  anterior  to  the  cephalic  testis  unites  with  the 
duct  from  this  latter  testis.  The  vas  deferens  immediately  expands  into 
a  long  much-coiled  seminal  vesicle  which  passes  anteriad  and  into  the 
cirrus  sac  (Fig.  69).  Inside  the  cirriis  sac  the  tube  continues  in  large 
coils ;  the  terminal  part  is  surrounded  bj'  the  cells  of  the  prostate  gland 
and  opens  to  the  surface  thru  a  short  hermaphroditic  duct.  There  is  a 
small  genital  papilla  (Fig.  71). 

Female  Reproductive  Organs. — Tlie  ovary  is  oval;  in  the  toto  speci- 
men it  is  0.098  mm.  long  and  0.088  mm.  wide,  and  in  the  sectioned  worm 
it  is  0.95  mm.  wide  and  0.134  mm.  thick.  It  is  median  in  position  and 
situated  midway  between  anterior  and  posterior  ends  of  the  body.  The 
oviduct  arises  at  the  dorsal  posterior  margin  and  passes  dorsad  and  pos- 
teriad into  Melilis'  gland.  This  gland  is  large  and  well  developed. 
Here  Laurer's  canal  is  given  off  and  passes  in  short  coils  to  the  dorsal 
surface.  Just  after  the  origin  of  Laurer  's  canal  a  short  common  vitelline 
duct  opens  into  the  ootype  and  the  oviduct  passes  ventrad.  It  expands 
to  form  the  initial  part  of  the  uterus,  turns  anteriad,  and  is  filled  witli 
masses  of  spermatoza.  The  expanded  portion  of  the  uterus  extends  an- 
teriad half  the  distance  to  the  caudal  testis  and  then  the  tube  contracts, 
passes  dorsad  and  in  a  winding  course  over  the  testes.  Anterior  to  the 
testes  it  turns  ventrad  and  enters  the  hermaphroditic  duct  on  the  pos- 
terior ventral  side.  The  vitellaria  extend  from  the  region  of  the  testes 
to  the  caudal  ends  of  the  digestive  ceca  and  consist  of  scattered  lobes, 
mostly  ventral  in  position.  Anteriorlj'  they  are  extracecal  but  behind 
the  ovary  they  are  intracecal  as  well. 

No  eggs  were  present  in  any  of  the  specimens. 

The  genital  pore  is  in  the  midventral  line,  just  posteror  to  the  bi- 
furcation of  the  alimentary  tract.  There  is  a  genital  sinus  but  no  geni- 
tal STicker. 


351]        NORTH  AMERICAN  PARAMPIIISTOMIDAE—STUNKARD  71 

Lymph  Sijstcm. — The  lymph  system  is  simih\r  to  that  desei-ibed  for 
A.  magnum  and  consists  of  the  three  longitudinal  canals  on  either  side 
of  the  body,  one  canal  lateral  to  each  cecum  and  a  pair,  one  dorsal  and 
the  other  ventral,  mesal  to  the  diverticulum  of  either  side.  The  seeon- 
darj'  branchings  could  not  be  traced  but  lymph  sinuses  are  present  in  sec- 
tions in  all  parts  of  the  body,  and  those  around  the  acetabulum  are  shown 
in  Figure  68. 

Excretory  System. — The  excretory  pore  is  median,  dorsal,  at  the 
level  of  the  cephalic  margin  of  the  acetabulum.  A  short  median  vesicle 
passes  veutrad  and  anteriad  and  divides  into  two  collecting  vesicles  as  in 
A.  magnum.  These  pass  ventrad  and  posteriad,  one  on  either  side,  loop 
around  the  caudal  ends  of  the  diverticula,  and  then  turn  anteriad,  wind- 
ing around  the  ceca  in  many  irregular  coils  so  that  in  sections  they  ap- 
pear lateral,  mesal,  ventral  or  dorsal  to  the  intestine ;  often  the  tube  is 
cut  two  or  three  times  in  the  same  section  or  a  single  section  may  show 
a  coil  encircling  the  cecum  for  half  or  more  of  its  circumference  (Fig. 
67).  Anterior  to  the  bifurcation  of  the  alimentary  tract  the  ducts  con- 
tinue in  the  lateral  areas  of  the  body  and  can  be  traced  almost  to  the  oral 
sucker. 

THE   GENUS   ZYGOCOTYLE 

The  only  known  form  with  which  the  paramphistomes  from  the  duck 
can  be  compared  is  Amphistoma  lunatum.  This  species  was  described 
by  Diesing  (1836)  ;  the  material  had  been  collected  by  Natterer  in  Brazil, 
South  America,  from  the  cecum  of  Anas  mclanotus,  A.  ipecutiri,  A. 
^noschata,  Himantopus  wUsonii,  and  also  from  the  cecum  of  Gcrvus 
dicJtotomus.  Fishoeder  secured  the  original  specimens  from  the  Vienna 
museum  and  (1903)  gave  a  more  extended  description  of  the  form,  altho 
his  study  was  restricted  to  the  examination  of  toto  preparations.  He 
stated  that  the  citation  of  Cervtis  dichotomus  as  a  host  of  this  form  is 
probably  an  error,  and  the  same  suspicion  had  been  mentioned  by  Diesing 
(1850).  It  is  at  once  apparent  that  the  present  species  is  very  similar 
to  A.  lunatum.  Both  are  parasites  of  American  ducks,  and  are  the  only 
paramphistomes  at  present  knowai  from  avian  hosts.  They  are  nearly 
equal  in  size,  are  similar  in  shape,  have  a  subtcrminal  oral  sucker,  re- 
productive sj'stems  that  compare  very  closely,  digestive  tracts  similar 
in  character,  and  acotabula  of  the  same  form  consisting  of  an  anterior 
section  and  a  posterior  overhanging  lip  which  terminates  on  either  side 
in  a  small  cone-like  projection. 

Atnphistoma  lunatum  has  been  placed  as  an  appendix  to  every  classi- 
fication of  the  paramphistomes  that  has  ever  been  attempted.  With  the 
discovery  of  a  form  so  similar,  the  two  must  belong  together  and  a 
new  genus  is  proposed  to  contain  the  two  species.     The  peculiar  divided 


72  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [352 

condition  of  the  acetabulum  suggested  the  name  Zygoeotyh^  as  appropriate 
for  this  genus.  Zijgocotylr  ccratosa  has  been  designated  as  t\'pe  and  in 
the  genus  is  included  also  the  species  Amphistoma  hinatum. 

As  diagnostic  characters  of  the  genus  Zygocotyle  may  be  mentioned 
the  subterminal  oral  sucker,  the  posterior  sucker  divided  or  provided 
■with  caudal  overhanging  lip,  absence  of  cirrus  sac  and  separate  openings 
of  the  male  and  female  ducts.  Others  will  undoubtedly  appear  when 
the  character  of  the  excretory  and  lymph  systems  are  known.  The  genus 
Zygocotyle  differs  from  all  other  known  genera  of  the  Paramphistomidae 
in  the  ventral  position  of  the  oral  sucker  and  the  peculiar  character  of 
the  acetabulum.  It  differs  from  the  Gastrodiscinae  in  the  shape  of  body 
and  absence  of  ventral  papillae,  and  from  the  Gastrothylacinae  in  the  ab- 
sence of  the  ventral  poiich.  In  the  lobed  testes  and  absence  of  cirrus 
sac  it  agrees  with  the  Paramphistominae,  but  the  oral  evagiuations  ex- 
clude it  from  that  group.  The  absence  of  ciri'us  sac  and  the  lobed  form 
of  the  testes  will  not  permit  its  inclusion  with  the  Cladorchiuae.  The 
characters  of  the  Diplodiscinae  are  so  poorly  defuied  that  a  comparison 
is  unsatisfactory ;  in  this  group  however,  a  cirrus  sac  is  present  and  both 
suckei'S  are  terminal.  As  none  of  the  existing  subfamilies  will  include 
the  genus,  a  new  subfamily  will  probably  have  to  be  made  to  contain  it. 
Since  the  present  classification  of  the  Paramphistomidae  is  somewhat  un- 
certain, and  the  structure  of  the  excretory  and  lymph  systems  of  this 
genus  are  as  yet  imkuowu,  no  further  attempt  at  classification  of  the 
group  is  made  at  this  time. 

ZYGOCOTYLE  CEEATOSA  Stuukard  1916 
[Figures  72  to  79] 

The  material  of  this  sj^ecies  consists  of  eight  specimens  from  tlie  in- 
testine of  Anas  platyrhynchos  from  Rock  County,  Nebraska.  The  intes- 
tine of  the  duck  had  been  cut  open  in  places  and  together  with  its  con- 
,tents  preserved  in  formalin.  The  fisation  of  the  parasites  is  so  poor 
that  the  excretory  and  lymph  system  can  not  be  traced,  altho  remnants 
of  both  appear  in  sections. 

These  worms  (Fig.  72.)  vary  in  length  from  3  to  6  mm.  and  in  width 
from  1.45  to  2.14  mm.  In  dorsal  or  ventral  aspect  they  are  elongate  oval 
jn  shape  with  the  acetabulum  forming  a  small  terminal  projection.  The 
cross  section  is  a  flattened  oval  and  toward  the  ends  of  the  body  becomes 
more  circular.  The  acetabulum  is  subterminal  and  consists  of  two  parts 
(Fig.  77),  an  anterior  part  extending  dorsally  and  anteriority  into  the 
body  and  a  posterior  overhanging  lip  which  terminates  on  either  .side 
^n  a  little  horn  or  conical  projection  0.12  to  0.2  mm.  in  length.      The 


353]        XORTH  AMERICAS  PARAMPHISTOMIDAE—STUSKARD  73 

.cephalic  part  extends  anteriad  about  0.46  mm.  from  the  anterior  margin 
of  the  opening  of  the  sucker.  The  opening  of  the  acetabulum  is  oval 
approximately  1.1  mm.  in  length  and  0.74  mm.  in  diameter.  The  sep- 
tum or  partition  which  divides  the  sucker  extends  almost  to  the  opening 
and  appears  to  separate  an  anterior  circular  part  from  the  remaining 
portion  but  there  is  a  single  oval  opening  of  the  acetabulum. 

The  cuticula  is  unarmed,  slightly  thicker  on  the  dorsal  surface.  On 
the  ventral  surface  it  is  about  12/t  in  thickness  and  reaches  30/i  in  thick- 
jiess  on  the  dorsal  surface.  It  is  not  homogeneous,  but  is  traversal  by 
fine  crinkled  lines  extending  from  internal  to  external  surfaces,  which 
give  it  a  reticulated  appearance.  The  entire  dorsal  surface  of  the  body 
is  underlaid  with  large  gland  cells  filled  with  a  substance  staining  deeply 
^vith  haematoxylin ;  and  their  ducts  lead  to  the  dorsal  surface.  The  eon- 
tents  of  the  gland  cells  and  their  ducts  have  the  same  appearance  and 
staining  reaction  as  the  cuticula  of  the  external  surface.  The  dermo- 
inuscular  sac  consists  of  the  usual  circular,  longitudinal,  and  oblique 
layers,  the  circular  layer  is  next  to  the  cuticula.  From  the  body  wall 
there  are  many  large  dorso-ventral  muscle  strands  extending  thru  the 
body. 

Alimentary  Tract. — The  oral  sucker  is  subterminal,  circular  or 
slightly  oval  in  shape,  0.37  to  0.53  mm.  in  diameter.  The  oral  evagina- 
tions  are  0.15  to  0.22  ram.  in  length  and  0.07  to  0.1  mm.  broad :  they 
branch  one  on  either  side  from  a  common  sinus  (Fig.  74)  which  opens 
into  the  dorsal  side  of  the  posterior  part  of  the  oi'al  sucker.  The  esoph- 
agus leads  from  the  oral  sucker  to  the  intestine ;  it  is  0.05  to  0.37  mm. 
jn  length  and  is  surrounded  by  a  layer  of  deeply  staining  cells.  Its 
caudal  portion  is  surrounded  by  an  esophageal  bulb.  This  structure  is 
oval,  0.2  to  0.45  mm.  in  length,  0.18  to  0.23  mm.  in  width,  and  0.35  mm. 
in  thickness  in  the  specimen  cut  in  cross  sections.  It  is  situated  obliquely 
in  the  body,  the  anterior  end  is  ventral  and  the  posterior  end  more  dorsal 
in  position.  The  muscles  are  not  arranged  in  concentric  lamellae  as  in 
the  previously  described  paramphistomes ;  there  is  a  capsule  of  external 
longitudinal  fibers  and  the  body  of  the  organ  is  composed  of  fibers  ex- 
tending on  the  sides  from  the  central  canal  to  the  external  capsule  and 
above  and  below  the  canal  the  fibers  extend  across  from  the  lateral  walls 
of  the  bulb  (Fig.  73).  The  alimentary  tract  is  lined  with  cuticula  to 
the  bifurcation.  The  eeca  are  flattened  laterally  and  the  lateral  walls 
are  sinuous  giving  them  a  very  irregular  appearance.  They  have  a  mus- 
cular wall  composed  of  outer  circular  and  inner  longitudinal  fibers  and 
extend  almost  to  the  opening  of  the  acetabulum,  about  0.1  to  0.15  mm. 
intervening.     They  terminate  just  caudad  of  the  excretory  pore. 

Male  Reproductive  Organs. — The  testes  lie  one  behind  the  other  in 


74  JLLIXOIS  BIOLOGICAL  MONOGRAPHS  [354 

the  median  line,  the  eandal  testis  is  almost  in  the  center  of  the  body,  and 
tlie  cephalic  testis  is  about  0.2  mm.  in  front  of  it.  They  are  about  the 
same  size,  lobulated,  oval,  crosswise  of  the  body,  almost  touching  the 
cecum  of  either  side.  They  are  ventral  in  position,  almost  touching  the 
ventral  body  wall  and  not  extending  far  into  the  dorsal  half  of  the  wonu. 
The}'  vary  in  size  from  0.2  by  0.3  mm.  in  the  smallest  to  0.55  by  0.78  mm. 
in  the  largest  specimen.  The  vasa  efferentia  arise  from  the  anterior 
dorsal  margins,  the  right  tube  from  the  anterior  and  the  left  tube  from 
the  posterior  testis.  Near  the  genital  pore  they  unite  and  form  a  much 
coiled  seminal  vesicle  which  has  a  thickened  muscular  wall.  This  struc- 
ture extends  thru  twenty-five  cross  sections  cut  10^  thick.  The  termi- 
nal part  tliat  leads  ventrad  to  the  genital  pore  is  expanded,  the  walls  are 
thinner,  and  this  part  is  siirrounded  by  the  cells  of  prostate  gland.  A 
cirrus  sac  is  absent,  the  male  and  female  tubes  open  to  the  exterior  in- 
dependently at  the  apex  of  a  slight  ventral  prominence.  The  opening 
of  the  male  duct  is  immediately  anterior  to  that  of  the  female  (Fig.  78). 

Female  Reproductive  Organs. — The  ovary  is  oval,  lobulated,  cross- 
wise of  the  body,  about  the  shorter  diameter  of  the  testis  behind  that  or- 
gan. In  the  smallest  specimens  it  is  0.2  by  0.33  mm.  and  in  the  largest 
0.33  by  0.52  mm.  The  oviduct  arises  at  the  dorsal  margin  as  a  ver.v  small 
tube  and  passes  dorsad  where  Laurer's  canal  is  given  off.  This  canal 
winds  in  short  curves  to  the  dorsal  surface,  opening  anterior  to  the  ex- 
cretory pore  (Fig.  79).  After  the  origin  of  Laurer's  canal  the  oviduct 
passes  posteriad  and  ventrad  into  Melilis'  gland  where  a  short  common 
vitelline  duct  is  received.  The  uterus  then  coils  irregularly  in  close  folds 
to  the  genital  pore.  The  uterine  coils  are  largely  in  the  dorsal  part  of 
the  worm  altho  they  may  extend  into  the  ventral  portion  and  coil  around 
the  testes.  Laterally  the  coils  of  the  uterus  are  limited  by  the  ceca.  The 
terminal  part  has  a  slight  thickening  of  the  wall  but  not  a  distinct  de- 
limited metraterm.  The  vitellaria  are  well  developed,  large  follicles  ex- 
tending in  the  extracecal  areas  from  the  level  of  the  pssterior  edge  of 
the  oral  sucker  to  the  anterior  margin  of  the  opening  of  the  acetabulum. 
They  are  limited  medially  bj-  the  ceca  and  laterally  extend  almost  to  the 
body  wall.     They  are  more  ventral  than  dorsal  in  position. 

Eggs  are  present  in  large  numbers.  In  size  they  average  0.14  by 
0.083  mm. 

Comparison. — Zijgocotyle  ccratosa  agrees  with  Z.  lu')iata  in  length, 
width,  and  size  of  oral  sucker,  but  in  the  former  species  the  oral  evagi- 
nations  are  smaller,  the  esophagus  is  much  shorter,  the  testes  and  ovary 
are  oval  and  lobed  instead  of  circular,  and  the  ceca  do  not  extend  to  the 
opening  of  the  acetabulum.  In  Z.  ccratosa  the  acetabulum  is  nearer  the 
ovary,  and  the  vitellaria  are  entirely  extracecal  while  in  Z.  lunata  they 
extend  between  the  ceca. 


355]        NORTH  AMERICAN.  PARAMPHISTOMIDAE—STUNKARD  75 

CLASSIFICATIOX  OF   THE  FAMILY 

Our  present  classification  of  the  Paramphistomidae  is  lai-gely  the 
result  of  the  work  of  Mouticelli,  Otto,  Fischoeder,  Colin,  Dpday,  .Stiles 
and  Goldberger,  Looss,  and  Odhner. 

The  first  division  of  the  group  was  made  by  I\Iontieelli  (1892) 
when  he  separated  Gastrodiscus  from  the  rest  and  created  the  subfamily 
Gastrodiscinae.  Fischoeder  in  a  series  of  papei's  described  several  spe- 
cies from  mammals,  and  formulated  (1903)  the  second  scheme  of  classi- 
fication. He  created  two  subfamilies :  Paramphistominae  in  which  the 
testes  are  lobed,  and  paired  oral  evaginations  and  cirrus  sac  are  absent ; 
and  Cladorchinae  characterized  by  branched  testes  and  the  presence  of 
paired  oral  evaginations  and  cirrus  sac.  Recent  additions  to  our  knowl- 
edge of  the  family  have,  however,  rendered  it  difficult  to  use  these  dis- 
tinctions satisfactoril3\  Cohn  (1904)  created  the  subfamily  Diplodisc- 
inae  to  contain  the  genera  Diplodiscus,  Opisthodiscus,  and  Catadiscus. 
He  characterized  the  subfamily  as  follows:  "Amphistomiden  von  ged- 
rungener,  konischer  Form  und  ruuden  Quersehnitt.  Mundsaugnapf  gut 
ausgebildet,  mit  zwei  retrodorsal  Tasehen.  Ein  grosser  Endsaugnapf, 
iiber  welehem  dorsal  der  Excretionsporus  liegt.  Mundoffnung  termi- 
nal, Darmschenkel  bis  zu  Endsaugnapf  reichend,  relativ  sehr  breit. 
Leben  im  Enddarm  von  Amphibien  und  Reptilien."  The  characteriza- 
tion is  inadequate,  since  the  anatomical  features  are  shared  bj'  almost 
half  the  members  of  the  family,  and  obviously  further  study  of  this 
group  is  necessary  to  establish  its  validity  and  determine  its  true  diag- 
nostic features. 

Stiles  and  Goldberger  (1910)  proposed  a  new  classification  of  the 
group.  They  created  a  new  superfamily  Paramphistomoidea  to  contain 
the  forms  previously  classed  as  amphistomes.  They  removed  Gastrodis- 
cus Leuck.,  and  Homalogaster  Poir.  from  Fischoeder 's  subfamily  Clad- 
orchinae and  created  a  new  family  Gastrodiscidae  to  contain  these  gen- 
era. They  created  another  new  family  Gastrothjdacidae  to  contain  the 
general  Gastrothylax,  Wellmanius,  Carmyerius,  and  Fischoederius.  The 
family  Paramphistomidae  and  the  two  cited  above  comprise  the  three 
families  in  the  superfamily  Paramphistomoidea.  Stiles  and  Goldberger 
also  created  a  new  subfamily  Stephanopharynginae  to  contain  the  genus 
Stephanopharj-nx,  and  added  the  new  genus  Cotylophoron  to  the  sub- 
family Paramphistominae.  They  recognize  further  the  subfamily  Dip- 
lodiscinae  Cohn  and  list  the  four  subfamilies  Paramphistominae,  Cla- 
dorchinae, Diplodiscinae,  and  Stephanopharynginae  in  the  familj-  Par- 
amphistomidae. They  placed  Balanorchis  in  the  subfamily  Cladorchinae 
notwithstanding  Fischoeder  "s  statement  that  such  an  arrangement  could 
not  be  considered. 


76  ILUXOIS  BIOLOGICAL  MONOGRAPHS  [356 

Braiin  (1911)  reviewing  the  article,  objects  to  the  rank  of  superfam- 
ily  for  the  paraniphistomes  and  says  placing  them  on  an  equality  of  rank 
with  the  Fascioloidea  is  not  justifiable. 

The  work  of  Stiles  and  Goldberger  is  criticized  at  the  hands  of 
Odhner  (1911)  as  follows:  "Dies  alles  zeigt  nun  evident,  wie  wenig 
Verstandnis  die  betreffenden  Autoren  fiir  die  moderne  natiirliche 
Digeneusystematik  habeu Mir  scheint  nun  diese  "Argu- 
mentation" ebenso  wie  viel  anders  (die  ueue  topographische  Terminol- 

ogie)  in  derselben  arbeit  sehr  "unwise"  zu  sein die  Amphistomen 

entsprechen  im  systematischen  Range  einer  einzelnen  Distomenfamilie 
imd  nicht,  wie  Stiles  and  Goldberger  gelaubt  haben,  der  Summe  samt- 
licher  dieser  Familien." 

Looss  (1912)  also  gives  a  critical  review  of  the  paper:  Die  Charak- 
terisierung  der  Arten,  Gattungen  usw.  baut  sicli  auf,  einerseits  auf  eine 
pedantisch  ins  einzelue  gehende  Analyse  iind  Beschreibung  der  Korper- 
form  und  der  Topographic  von  Darm  und  Genitalapparat,  anderseits 
auf  eine  konsequente  Ignorierung  der  beiden  Tatsachen,  dass  die  Tiere, 
als  Organismen,  innerhalb  gewisser  Grenzen  natiirlich  variieren,  und 
dass  Korperform  sowohl  wie  Topograpliie  der  Organs  mit  dem  Wachstum 
gesetzmassige,  mit  der  Kontraktion  a  priori  nicht  bestimmbare  Verander- 
ungen  erleiden.  Der  Aufbau  von  Lymph — und  Excretionsapparat 
bleibt  vollig  unberiicksichtigt.  Dass  die  Amphistomen  ein  "Lymphge- 
fasssystem"  tiberhaupt  besitzen,  scheint  den  Autoren  unbekannt  zu 
sein. " 

The  classification  of  Stiles  and  Goldberger  as  pointed  out  by  other 
authors  is  based  on  superficial  characters  and  the  elevation  in  rank  of 
the  family  and  groups  within  the  family  is  in  most  cases  unwarranted. 
However,  the  subfamily  Gastrothylacinae  of  these  authors  appears  to  be 
clearly  distinguished  by  the  presence  of  the  large  ventral  pouch,  and  in 
my  opinion  should  be  retained. 

Looss  (1912)  considers  the  lymph  and  excretory  systems  of  major 
importance  in  classification.  As  characters  of  the  new  subfamily  Schiz- 
amphistominae  he  mentioned  the  type  of  Ij^mph  and  excretory  systems. 
Since  the  lymph  system  has  not  yet  been  described  in  other  subfamilies, 
the  former  diagnoses  based  on  body  form,  tj'pes  of  digestive  and  repro- 
ductive systems,  presence  of  ventral  pouch,  etc.,  must  be  retained  for  the 
present.  Moreover,  since  so  many  of  the  forms  are  incompletely  de- 
scribed, and  considerable  diiferenee  of  opinion  exists  in  regard  to  the 
taxonomic  value  of  the  different  features,  the  classification  of  the  group 
is  still  imcei-tain.  As  Looss  (1912)  says,  "Jeder  Klassifikationversuch, 
der  der  bau  von  Excretions — und  Lymphgefasssystem  ausser  acht  lasst, 
mag  sich  wohl  einen  Klassifikationsversuch  nennen,  kann  aber  niemals 


357]        XORTH  AMERICAN  PARAMPHJSTOMIDAE—STUNKARD  77 

Ansprucli  darauf  erheben,  als  naturlicher  oder  (was  dasselbe  ist) 
wissensehaftlieher  Klassifikationsversuch  anerkauut  zii  werden."  In  the 
same  article  he  states  that  for  many  years  he  has  been  engaged  in  prepar- 
ing a  revision  of  the  amphistomes  but  has  not  yet  completed  the  work 
which  will  present  a  classification  based  on  the  structure  of  the  lymph 
and  excretory  systems  and  the  eopulatory  apparatus. 

The  only  arrangements  of  the  genera  of  the  family  that  have  been 
made  heretofore  are  those  of  Fishoeder  and  of  Stiles  and  Goldberger. 
The  classification  of  Fischoeder  does  not  appear  adequate  and  that  of 
Stiles  and  Goldberger  is  far  from  satisfactory,  but  for  sake  of  complete- 
ness both  are  appended  in  outline. 

Classification  of  Fischoeder  (1903) 
Paramphistomidae 

Paramphistominae 
Paramphistomum 
Gastrothylax 
Stephanopharynx 

Species  inquirendae,     A.  gigantocotyle 
A.  explanatum 
Cladorchinae 
Cladorchis 
Gastrodiscus 
Homalogaster 
Diplodiscus 
Chiorchis 

Species  inquirendae ;  A.  liawkesi,  A.  collinsi,  A.  orna- 
tum,  A.  papillatum,  A.  tuherculatum,  A.  emarginatum, 
and  A  lunatum. 
(Subfamily  nov.) 
Balanorchis 

Classification  of  Stiles  and  Goldberger  (1910) 
Paramphistomoidae 
Gastrodiscidae 

Gastrodiscus  ' 

Homalogaster 
Gastrothylacidae 

Gastrothylaeinae 
Gastrothylax 
Wellmanius 
Carmyerius 
Fischoederius 


78  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [358 

Paramphistomidae 

Paramphistominae 

Paramphistomum 

Cotylophoron 
Cladorchinae 

Cladorehis 

Taxoreliis 

Chiorchis 

Mierorcliis 

Pseudocladorchis 

Pseudodiseus 

Balanorehis 

Watsonius 

Pfenderius 
Diplodiscinae 

Diplodiscus 

Catadiseus 

Opisthodiscus 
Steplianopharynginae 

Stephanopharynx 

As  a  result  of  mj^  studies  on  this  family,  certain  data  have  been 
added  and  some  doubtful  points  cleared  up.  The  discovery  of  the  two 
species  of  the  new  genus  Alassostoma  and  the  demonstration  of  their  po- 
sition as  members  of  a  new  genus  in  the  subfamily  Schizamphistomiuae 
Looss  establishes  that  group.  The  description  of  the  new  genus  and 
species  Zygocotyle  ceratosa  throws  considerable  light  on  the  previously 
isolated  and  obscure  species  A.  lunatum  Dies.  In  conclusion  I  present 
a  tentative  revision  of  the  paramphistomes.  In  the  main  it  is  my  inter- 
pretation of  the  status  of  the  groiip  and  its  subdivisions.  The  new  genera 
of  Stiles  and  Goldberger  are  included  ■(vithout  comment  altho  certain  au- 
thors do  not  recognize  their  validity.  I  have  had  no  opportunity  to  work 
on  this  material  and  consequently  any  judgment  on  my  part  must  appear 
unwarranted..  Because  of  the  scarcity  of  known  forms  and  the  incom- 
pleteness of  most  of  the  descriptions  it  is  impossible  to  present  a  final 
classification.  The  following  arrangement  is  provisional  and  likely  to 
be  replaced  whenever  a  natural  system  can  be  formulated  for  the  famih-. 

Paramphistomidae  5'ischoeder  1901 
Gastrodiscinae  MonticeUi  1892 
Gastrodiscus 
Homalogaster 
Paramphistominae  Fischoeder  1901 


359]        NORTH  AMERICAS  PARAMPHISTOMIDAE—STUNKARD 

Paramphistomum 

Stephanopharynx 

Cotyloplioron 
Cladorchinae  Fischoeder  1901 

Cladorehis 

Taxorchis 

Chiorchis 

Pseudodiscus 

Microrchis 

Pseudocladorchis 

Watsonius 

Pfenderius 
Diplodiscinae  Colm  1904 

Diplodiseus 

Opisthodiscus 

Catadiscus 
Gastrothylacinae  Stiles  aud  Goldberger  1910 

Gastrothylax 

"Wellmanius 

Carmyerius 

Fischoederius 
Schizamphistominae  Looss  1912 

Schizamphistomum 

{Gen.  710V.)  spinulosum 

Alassostoma 

Genera  of  uncertain  position 
(new  subfamily)  Fischoeder  1903 

Balanorcliis 

-(new  subfamily)  see  text  p.  71 


Zygocotyle 


ILLINOIS  BIOLOGICAL  MONOGRAPHS  [360 


RELATION  OP  THE  FAMILIES  TO  THE  ORDER 

The  trematodes  are  generally  regarded  as  descended  from  a  tur- 
bellarian-like  ancestor  which  possessed  a  posterior  sucker.  With  the 
assumption  of  the  parasitic  habit  adaptations  began  in  various  directions. 
The  ectoparasitic  forms  retained  many  of  their  former  characters  while 
the  added  protection  and  food  supply  afforded  those  specializing  toward 
endoparasitic  existence  provided  for  perpetuation  and  distribution  of 
the  species  thru  the  excessive  development  of  the  reproductive  apparatus. 
The  development  of  the  ectoparasitic  forms  is  simple  and  direct  while 
that  of  most  if  not  all  endoparasites  has  been  complicated  bv  the  inter- 
polation of  one  or  even  more  secondary  or  intermediate  hosts. 

The  differences  in  type  of  adhesive  apparatus  may  in  a  general  way 
be  explained  thru  differences  in  habit.  The  oral  sucker  has  developed 
thru  continued  adhesion  by  the  anterior  end  in  maintaining  position,  in 
locomotion,  and  in  securing  food.  In  the  Gasterostomidae  the  mouth  is 
on  the  ventral  surface  and  an  independent  anterior  sucker  is  developed, 
altho  this  is  undoubtedly  a  secondary  feature,  as  in  the  cercariae  of  these 
forms  there  is  a  single  anterior  oral  sucker.  In  response  to  the  constant 
necessity  for  strong  adhesion  the  ectoparasitic  species  have  developed 
accessory  posterior  organs  of  attachment,  while  in  most  of  the  endopara- 
sitic forms  the  acetabulum  has  migrated  auteriad  or  disappeared  entirely. 

The  general  classification  of  Monticelli,  which  is  followed  in  this 
paper,  is  based  primarily  on  the  character  of  the  adhesive  apparatus. 
In  the  Heterocotylea  the  posterior  sucker  has  been  replaced  by  a  disc 
which  bears  suckers  and  hooks ;  in  the  Aspidocotylea  the  acetabulum  has 
become  specialized  into  a  multiloculate  adhesive  organ ;  and  in  the  Mal- 
aeocotylea  the  acetabulum  maj'  be  retained  in  its  primitive  terminal  posi- 
tion, or  it  may  liave  migrated  anteriorly,  in  certain  cases  being  reduced 
and  in  others  disappearing  entirely.  In  the  young  individuals  of  many 
forms  in  each  of  the  tliree  groups  there  is  a  single  posterior  sucker  and 
this  fact  adds  weight  to  the  theory  that  the  present  groups  are  descended 
from  a  primitive  form  with  a  simple  posterior  sucker.  In  the  young 
stages  of  all  the  Aspidogastridae  there  is  a  simple  posterior  sucker  and 
the  worm  closely  resembles  a  young  distomc.  In  the  early  stages  of  the 
Heterocotylea  the  reversion  to  the  ancestral  conditions  is  not  so  complete, 
and  specialization  in  this  group  shows  clearly  that  it  is  widelj'  separated 


361]        XORTH  AMERICAX  PARAMPHISTOMIDAE—STCWKARD  81 

from  the  other  two  suborders  which  thru  the  presence  of  similar  young 
forms  appear  to  be  more  closely  related. 

The  morphological  structure  and  direct  development  of  the  Polys- 
tomidae  at  once  places  them  with  the  Heterocotylea.  In  the  adoption 
of  an  endoparasitie  mode  of  life,  however,  thy  show  a  distinct  departure 
from  the  other  members  of  the  suborder.  The  present  study  of  the 
Polystomidae  has  emphasized  the  unusual  morphological  variation  and 
M-ide  geographic  distribution  which  exists  in  the  family.  This  may  mean 
either  that  the  family  is  verj-  old  and  has  been  subjected  to  conditions 
producing  wide  variation,  or  that  the  group  reallj^  lacks  family  entity 
and  consists  of  various  heterocotylean  forms  which  have  specialized  in 
the  direction  of  an  endoparasitie  habit  and  that  the  morphological  re- 
semblance is  cenogenetic. 

Pratt  (1908)  re\-iews  the  literature  and  arguments  for  convergent 
development  which  are  based  on  trematode'  morphology.  Johnston 
(1914)  argues  for  divergence  as  the  true  explanation  of  the  variation  of 
the  species  of  Pueumoeneces,  Gorgoderinae,  Braehycoelinae,  etc.,  and 
believes  that  the  elucidation  of  trematode  phylogeuy  may  be  sought  in 
the  study  of  the  relationships  between  the  distribution  of  trematode 
parasites  and  the  distribution  of  their  hosts.  No  doubt  the  likenesses 
and  dilferences  in  the  structure  of  present  species  are  the  result  of  both 
convergence  and  divergence ;  yet  it  seems  that  the  distributional  factor 
emphasized  by  Johnston  is  not  of  major  importance.  Parasitic  distri- 
bution coidd  precede  the  distribution  of  the  primaiy  and  secondary  hosts 
only  in  case  the  parasites  changed  to  new  primary  or  secondary  hosts. 
Biit  today  more  than  one  species  may  serve  as  primary  or  secondary 
host;  the  parasite  is  probably  in  a  restricted  degree  able  to  adapt  its 
life  history  physiologically  so  other  species  may  serve  as  hosts,  and 
primitively  this  adaptability  may  have  been  greater  than  now.  The 
disti'ibution  of  the  parasites  certainly  depends  to  a  large  extent  on  the 
distribution  of  the  primary  host,  and  to  a  less  extent  on  the  distribution 
of  the  secondary  host,  but  the  presence  of  two  similar  parasites  in  the 
same  region  does  not  prove  that  their  hosts  had  primitively  the  same 
or  different  parasites.  The  life  history  of  the  trematodes  is  so  imper- 
fectly known  that  at  present  no  final  decision  can  be  made  on  this  basis. 

The  wide  variation  in  structure  of  the  members  of  the  genus  Poly- 
stoma  can  not  be  adequately  explained  thru  migration,  or  thru  differ- 
ences in  the  age  of  the  parasite,  type  of  host,  or  location  in  the  host.  In 
the  genus  so  far  as  is  known,  the  long  uterus  containing  many  eggs  is 
confined  to  species  infesting  the  urinary  bladder  of  amphibian  hosts  of 
the  Old  World.  However  in  respect  to  other  characters,  e.  g.,  the  shape 
of  the  caudal  disc  and  absence  of  great  hooks,  these  amphibian  forms  of 


82  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [362 

the  Eastern  hemisphere  disagree  with  each  other  and  agree  with  forms 
parasitic  in  the  urinary  bladder  and  oral  cavity  of  North  American 
turtles.  The  turtle  parasites  have  a  very  similar  structure,  whether 
parasitic  in  the  urinary  bladder  or  in  the  pharyngeal  cavity.  Further- 
more, if  tlie  observations  of  Zeller  are  correct  and  the  individuals  of 
P.  integcrrimutn  becoming  mature  on  the  gills  of  tadpoles  lack  external 
vaginae  and  have  a  spherical  testis  and  a  single  egg  in  the  uterus,  one  is 
entirely  at  a  loss  to  explain  the  variation  existing  in  the  genus. 

In  the  Aspidogastridae  the  young  individuals  have  an  oral  sucker 
and  a  small  posterior  acetabulum  without  dividing  ridges,  and  very 
closely  resemble  young  distomes.  The  mode  of  infection  is  almost  en- 
tirely unknown,  and  this  oifers  a  promising  field  for  investigation.  The 
discovery  of  the  sexual  form  of  Stichocotyle  by  Odhner  (1898)  estab- 
lishes the  fact  that  at  least  one  species  of  the  Aspidogastridae  has  an 
intermediate  host.  Nickerson  (1895)  observes,  "Owing  to  the  well 
known  tendency  of  fresh  water  conditions  to  obliterate  larval  life,  it  may 
well  be  that  Aspidogaster  has  secondarily  lost  a  more  or  less  compli- 
cated series  of  changes,  which  have  been  retained  by  its  relatives  inhabit- 
ing salt  water."  The  presence  within  the  family  of  both  direct  and 
indirect  development,  together  with  other  characters  common  to  both 
the  Heterocotylea  and  Malacocotylea  designate  it  as  an  intermediate 
group.  The  morphological  structure  is  similar  to  that  of  the  Mala- 
cocotylea while  the  manner  of  development  is  similar  to  that  of  the 
Heterocotylea.  Whether  the  Aspidogastridae  are  primitive  forms  or 
are  secondarily  degenerate  is  as  yet  undecided.  The  simj^le  and  archaic 
character  of  the  intestine,  the  eye  spots,  the  direct  development  and  the 
ectoparasitic  habit  as  it  occurs  in  the  family,  together  with  the  para- 
sitic infection  of  moUuscs  by  adult  forms  strongly  suggests  a  very  primi- 
tive and  ancient  group.  It  is  probable  that  complete  evidence  concern- 
ing the  structure  and  life  history  of  this  family  M'ould  go  a  long  way 
toward  solving  the  problem  of  whether  the  invertebrate  or  the  vertebrate 
is  the  original  host  and  the  attendant  problem  of  the  origin  of  double 
hosts. 

The  Paramphistomidae  appear  to  be  a  primitive  family  of  the 
Malacocotylea  that  have  retained  the  original  caudal  sucker,  altho 
certain  species  show  specializations  of  the  organ  from  the  simple  spher- 
ical type.  Considerable  light  is  thrown  on  the  relationships  of  the 
Malacocotylea  by  the  recent  work  of  Odhner  on  a  natural  system  for  the 
digenetic  trematodes.  He  strongly  advocates  the  view  that  the  mono- 
stomes  are  a  group  which  have  no  family  entitj',  and  consist  of  individual 
forms  derived  from  various  distome  groups  which  have  alike  lost  the 
acetabulum.    Pointing  out  close  and  fundamental  agreement  in  internal 


363]        NORTH  AMERICAN  PARAMPHISTOMIDAE—STUNKARD  83 

structure  he  argues  that  the  mouostome  family  Angiodietyidae  is  really 
a  subfamily  of  the  Paramphistomidae.  He  shows  essential  morphological 
agreement  between  Distoma  quadrangulum  Daday  and  the  fish  amphis- 
tomes.  His  examination  of  the  original  specimen  of  Aspidocotyle  con- 
firms the  statement  of  Braun  (1879-1893)  that  this  form  belongs  to  the 
amphistomes,  altho  its  relation  to  the  other  members  of  the  group  is 
uncertain.  Further  he  states  that  the  Gasterostomidae  by  the  structure 
of  the  cercaria  as  shown  in  the  oral  sucker  and  the  presence  and  relations 
of  the  oral  evaginations,  doubtless  belongs  to  the  Paramphistomidae. 
His  derivation  of  the  gasterostomes  thus  from  amphistome-Iike  forms  of 
frogs  is  plausible  since  the  frogs  serve  as  food  for  the  hosts  of  the 
gasterostomes.  To  Odhner's  argument  may  be  added  that  the  divided 
condition  of  the  body  in  Gastrodiscus  recalls  the  similar  condition  in 
certain  Aspidogastridae  and  suggests  a  possible  relationship  between 
these  forms.  The  morphological  comparisons  of  Odhner  and  other 
writers  appear  to  show  very  clearly  that  divergence  and  convergence 
have  both  had  great  influence  on  the  phylogeny  of  certain  trematode 
families. 


84  ILLINOIS  BIOLOGICAL  MO.XOGRAPIIS  [364 


LIST  OF  NEW  SPECIES 

PAGE 

Alassostoma  magnum  - 66 

Alassostoma  parvum  69 

Polystomu  megacotyle  - 37 

Poly  stoma  microcotyle  39 

Poly  stoma  opacum  - 34 

Polystoma  orhiciilare  - 31 

Zygocotylc   ceratosa  - 72 

A  preliminary  description  was  given  in  the  Journal  of  Parasitology, 
3 :21-27. 


365]  XORTH  AMERICAN  POLYSTOMIDAE—STUKKARD 


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Creplin,  F.  C.  H. 

1844.  Endozoologische  Beitrage.     Arch.  f.  Naturg.,  10:112-133,  i  pi. 
Cunningham,  J.  T. 

1884.     A   New   Marine   Trematode   Belonging   to   the    Polystomidae.     Zool. 

Anz.,  7:399- 
1887.    On  Stichocotyle  iiephropis,  a  New  Trematode.    Trans.  Roy.  Soc.  Edinb., 
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Daday,  E.  von 

1907.     In     siidamerikanischen     Fischen     lebende     Trematoden-Arten.     Zool. 
Jahrb.,  Syst.,  24 :469-590,  6  pi. 
Delaroche,  F.  E. 

1811.     Sur  deux   animaux  vivant  sur  les  branchies  des  poissons.     N.   Bull. 
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Diesing,  K.  M. 

1836.     Monographic    der    Gattuiigen    Amphistoma    und    Diplodiscus.      Ann. 

Wien.  Mus.  Naturg.,   i  :235-26o,  3  pi. 
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1845.  Histoire  naturcllc  des  hclniiiithes  ou  vers  intestinaux.     Paris. 
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1901.     Die   Paraniphistomiden  der   Siiugethiere.     Zool.   Anz.,  24:367-375. 
1903.     Die      Paraniphistomiden      der     Saugethiere.       Zool.     Jahrb.,     Syst., 

17:485-660,   II   pi. 
Forbes,  S.  A. 

1896.     Cotylasl>is  iiisignc.     Rieii.  Rep.  St.  Lab.  Nat.  Hist.   Springfield,  III. 
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1789.     Beschreibungen     einiger     neuer     Eingevveidewiirmer.     Naturforscher, 

Halle,  24:101-162,  figs.  1-31.     (Cited  after  Stiles  and  Hassall,  1902-1912.) 
1791.     B'eytrage  zur  Naturgeschichte  der  Eingeweidewiirmer.     Naturforscher, 

Halle,  25:52-113,  17  figs.     (Cited  after  Stiles  and  Hassall,  1902-1912.) 


367]  XORTH  AMERICAS  POLYSTOMIDAE—STUNKARD  87 

GOLDSCHMIDT,  R. 

1902.     Untersuchungen  iiber  die  Eireifung,  Befruchtung  und  Zelltheilung  bei 

Polystomum  iiitegerriiiium  Rud.    Zeit.  f.  wiss.  Zool.,  71 :397-44S,  3  pi. 
1902a.  B'emerkungen    zur   Entwicklungsgeschichte    des   Polystomum   integer- 

rimuiit  Rud.     Zeit.  f.  wiss.  Zool.,  72:180-189,  11  figs. 
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Goto,  S. 

1894.     Studies  on  the  Ectoparasitic  Trematodes  of  Japan.     Jour.  Coll.  Sci., 

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1902.     Recherches  sur  la  maturation,  la  fecondation  et  la  developpement  du 
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1907.     Genito-intestinal  Canal  in  Polyclads.     Zool.  Anz.,  31  :643-644. 
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1888.    Trematoda.    Encyc.  Brit.  9  ed.,  23  :535-540. 
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1884.     Ueber  den  Zusammenhang  des  Eileiters  mit  dem  Verdauungscanal  bei 
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1899.    Ueber   den   Bau  von   Macraspis  clegans.    Ofvers.    Vet-Akad.   Fordh., 
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1912.     On  Some  Trematode  Parasites  of  .■Xustralian  Frogs.     Proc.  Linn.  Soc. 

X.  S.  Wales,  37 :285-362,  pi.  14-43. 
1914.     Trematode  Parasites  and  the  Relationships  and  Distribution  of  their 
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1899.    A  Statistical  Study  of  the  Parasites  of  the  Unionidae.     Bull.  III.  St. 
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KOFOID,    C.    A. 

1899.     On  the   Specific  Identity  of  Cotylaspis  iitsigitis  Leidy  and  P!atyasl>is 
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KuHL,  H.,  und  Hasselt,  J.  C.  van 

1822.     Polystoma  midac.    Isis,  1822:113-115.     (Cited  after  Braun,  1879-1893.) 

KUHN,  J. 

1829.    Description  d'un  nouvel  epizoaire  du  genre  Polystomum  qui  se  trouve 
sur  Ics  branchies  de  la  petite  roussette  (Squalus  catutus)  suivie  de  quelques 
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2 :  460-465. 
Leidy,  J. 

1851.     Helminthological    Contributions    II.      Proc.    Acad.    Nat.    Sci.    Phila., 

5  :224-227. 


88     .     \ORTH   AMERICAN    PARAMPHISTOMIDAE—STUNKARD       [368 

1857.  Observations  on   Entozoa  Found  in  the  Xaiades.     Proc.  Acad.   Xat. 
Sci.  Phila.,  9:18. 

1858.  Contributions    to    Helminthology.      Proc.     Acad.     Nat.     Sci.    Phila., 
10:110-112. 

1888.     Entozoa  of  the  Terrapin.     Proc.  Acad.  Nat.  Sci.  Phila.,  40:128. 
Linton,  E. 

1905.     Parasites  of  Fishes  of   Beaufort,   North   Carolina.     Bull.  Bur.  Fish., 
24:321-428,  34  pi. 
Looss,  A. 

1885.     Beitrage  zur  Kenntnis  der  Trematoden.     Zeit.  f.  wiss.  Zool.,  41  :390- 
446,  I  pi. 

1892.  Ueber     Amfhistomuiii     subclavatum     Rud.     und     seine     Entwicklung. 
Festschr.  Leuckart,  p.  147-168,  pi.  19-20. 

1893.  1st  der  Laurer's  Canal  der  Trematoden  eine  Vagina?    Centr.  f.  Bakt. 
u.  Par.,  13:808-819. 

1896.     Recherches    sur   la   Faune   parasitaire    de    I'Egjpt.      Premiere   partie, 

Mem.  de  ITnst.  egypt,  3:1-252,  16  pi. 
1899.    Weitere    Beitrage    zur    Kenntnis    der    Trematoden-Fauna    Aegyptens. 

Zool.  Jahrb.,  Syst.,  12:521-784. 

1902.  Ueber    neue    und    bekannte   Trematoden    aus    Seeschildkroten.     Zool. 
Jahrb.,  Syst.,  16:411-894,  pi.  21-32. 

1912.  Ueber  den  Bau  einiger  auscheinend  seltener  Treraatoden-Arten.  Zool. 
Jahrb.,  Suppl.,  15:323-366,  3  pi. 

LiJHE,  M. 

1909.     Parasitische    Plattwiirmer.      I,    Trematodes.      Die    Siisswasserfauna 
Deutschlands,  17:1-217,  188  figs. 
MacC.^llum,  G.  a. 

1913.  Fertilization  and  Egg-Laying  in  Microcoiyle  stenotomi-     Science,  n.  s., 
37:340-341- 

MacCallum,  G.  a.,  and  MacCallum,  W.  G. 

1913.    On  Aspidogaster  ringens  and  A.  kemostoma  n.  sp.    Zool.  Jahrb.,  Syst., 
34:245-256,  4  figs. 
MacCallum,  W.  G. 

1905.     On   Two    New    Amphistome    Parasites    of    Sumatran    Fishes.     Zool. 
Jahrb.,  Syst.,  22:667-678,  2  figs. 
Mace,  E. 

1880.     Des  Trematodes  parasites  des  Grenouilles.     Bull.   Soc.  d'etud.    scien. 
Finistere,  Morlaix,  31  pp.,  4  pi.     (Cited  after  B'raun,  1879-1893.) 

MONTICELLI.  F.   S. 

1892.     Cotylogaster  michaclis  n.g.,  n.  sp.,  e  revisione  degli  Aspidobothridae. 
Festschr.  Leuckart,  p.  166-214,  2  pi. 

1903.  Per  una  nouva   classificatione   degli    "Heterocotylea".     Monit.    zool. 
Ital.,   14:334-337- 

NiCKERSON,  W.    S. 

1895.     On  Stichocotyle  nephropis  Cunningham,  a  Parasite  of  the  American 
Lobster.     Zool.  Jahrb.,  Anat.,  8:447-480,  3  pi. 


369]  XORTH  AMERICAS  POLYSTOMIDAE—STUSKARD  89 

1902.     Cotologaster  occidcntalis  n.  sp.  and  a  Revision  of  the  Family  Aspido- 
bothridae.     Zool.  Johrb.,  Syst,  15  :S97-624,  2  pi. 
Odhner,  T. 

1898.  Uber  die  geschlechtsreife  Form  von  Stichocotyle  nepliropis  Cunning- 
ham.   Zool.  Anz.,  21  :509-5i3. 

1911.  Zum  natiirlichen  System  der  digenen  Trematoden,  I.  Zool.  .*\nz.,  37: 
181-191. 

1911a.    Zum  natiirlichen   System  der  digenen  Trematoden,  IV.     Zool.  .'\nz., 

38:513-531- 

1912.  Die  Homologien  der  weiblichen  Genitalwege  bei  den  Trematoden  und 
Cestoden.  Nebst  Bemerkungen  zum  natiirlichen  System  der  monogenen 
Trematoden.     Zool.  Anz.,  39:337-351. 

1913.  Noch  einmal  die  Homologien  der  weiblichen  Genitalwege  der  mono- 
genen Trematoden.    Zool.  Anz.,  41 :558-SS9. 

OSBORN,   H.   L. 

1898.    Observations  on  the  Anatomy  of  a  Species  of  Platyaspis  Found  Para- 
sitic on  the  Unionidae  of  Lake  Chautauqua.    Zool.  Bull.,  2 :5S-67,  6  figs. 
1904.     On  the  Habits  and  Structure  of  Cotylasfis  iiisignis  Leidy,  from  Lake 
Chautauqua,  N.  Y.    Zool.  Jahrb.,  Anat.,  21:201-243,  3  pi. 
Otto,  H.  R. 

1896.     Beitrage   zur  Anatomie  und   Histologic   der  Amphistomideii.     Dtsch. 
Zeit.  Thiermed.,  22:85-141,  30  figs. 
PocHE,  F. 

1907.  Einige  Bemerkungen  zur  Nomenclature  der  Trematoden.  Zool.  .\nz., 
31  :i24-i26. 

POISIER,  J. 

1886.     Trematodes    nouveau.x    ou    peu    connus.      Bull.    Soc.    Philom.    Paris, 

7  ser.,  10 :20-40,  4  pi. 
Pratt,  H.  S. 

1900.     Synopses  of  North  American   Invertebrates,   XII.     The  Trematodes. 

Part  I.    The  Heterocotylea  or  Monogenetic  Forms.     Amer.  Nat.,  34 :645- 

662,  50  figs- 

1908.  Parallel  Development  in  Trematodes.     Science,  u.  s.,  27 :489. 
RUDOLPHI,  C.  A. 

1801.    Bebachtungen  iiber  die  Eingeweidewiirmer.    Arch.  f.  Zool.  u.  Zootom., 

2:1-65. 
1809.     Entozoorum   sive   vermium   intestinalium   historia   naturalis.     Amste- 

laedami,  1809. 
1819.     Entozoorum  synopsis.    Berolini,  1819. 
St.  Remy,  G. 

1891.    Synopsis   des   Tremotodes    monogeneses       Rev.  Biol.    Nord.    France, 

4:1-92,  2  pi. 
i8g8.    Complement  du  synopsis  des  Trematodes  monogeneses.  Arch.  d.  Paras., 

I  :S2i-S7i,  6  figs. 
Stafford,  J. 

1896.    Anatomical  structure  of  Aspidogaster  conchicola.    Zool.  Jahrb.,  .Anat., 

9:477-542,  4  pl. 
1900.    Some  Undescribed  Trematodes.    Zool.  Jahrb.,  Syst.,  13:399-414,  i  pl. 


90  KORTH    AMERICAN    POLYSTOMIDAE—STUNKARD  [370 

1905.     Trematodes  from  Canadian  Vertebrates.    Zool.  Anz.,  28:681-694. 
Stewart,  F.  H. 

1914.    The  Anatomy  of  Polystomum  kachugae  n.  sp.  with  Notes  on  the  Genus 
Polystomum.    Rec.  Ind.  Mus.,  10:195-205,  4  pi. 
Stieda,   L. 

1870.    Uebcr  den  Ban  des  Polystomum  intcgerrimum.    Arch.  f.    Anat.  Phys. 
u.  Med.,  5:660-678,  I  pi. 
Stiles,  Ch.  W.,  and  Goldberger,  J. 

igio.    A  Study  of  the  Anatomy  of  Wahonius  watsoni  of  Man  and  of  Nine- 
teen  Allied   Trematode   Worms   of   the   Superfamily   Paramphistomoidea. 
Bull.  Hyg.  Lab.,  No.  60:1-264,  205  figs. 
Stiles,  Ch.  W.,  and  Hassall,  A. 

1902-1912.     Index-Catalogue  of  Medical  and  Veterinary  Zoology.     Bull.  Bur. 

Animal  Ind.,  No.  39. 
1908.    Index-Catalogue  of  Medical  and  Veterinary  Zoology.    Bull.  Hyg.  Lab., 
No.  37:89- 
Stunkard,  H.  W. 

1916.     On  the  Anatomy  and  Relationships  of  Some  North  American  Trema- 
todes.    Jour.  Par.,  3:21-27. 
Taschenberg,  O.  E. 

1879.    Zur    Systeraatik    der    Monogenetischen    Tematoden.      Zeit,    gesammt 
Naturwisscnsch.,    52:232-265. 
Treutler,  F.  A. 

1793-  Observationes  pathologico-anatomicae,  auctariam  ad  helminthologiam 
humani  corporis  continentes.  Diss,  in  praes.  Ch.  F.  Ludwig.  Lips.  (Cited 
after  Braun,  1879-1893.) 

VOELTZKOW,  A. 

1888.    Aspidogaster  conchicola.    Arb.  zool.-zootom.  Inst.  Wurzb.,  8:249-292, 

5   Pl. 
Walter,  E. 

1893.    Untersuchungen  uber  den  Bau  der  Trematoden.    Zeit.  f.  wiss.  Zool., 
56:189-243,  3  pl. 
Willemoes-Suhm,  R.  von 

1872.    Zur  Naturgeschichte  des  Polystomum  integerrimum  and  Polystomum 
ocellatum.    Zeit.  f.  wiss.  Zool.,  22 :29-39,  i  pl. 
Wright,   R.    R. 

1879.    Contributions  to  American  Helminthology.    Jour.  Proc.  Canad.  Inst, 
N.  S.,  I  :i-23,  2  pl. 
Wright,  R.  R.,  and  Macallum,  A.  B. 

1887.    Sphyranura  osleri.    Jour.  Morph.,  I  :i-48,  i  pi. 
Zeder,  J.  G.  H. 

1800.     Erster   Nachtrag   zur   Naturgeschichte    der     Eingeweidewiirmer   von 
J.  A.  G.  Goeze.    Leipzig,  1800. 
Zeller,  E. 

1872.    Untersuchungen  uber  die  Entwicklung  und  Bau  des  Polystomum  in- 
tegerrimum Rud.    Zeit.  f.  wiss.  Zool.,  22:1-28,  2  pl. 
1876.    Weiterer  Beitrag  zur  Kenntniss  der  Polystomen.    Zeit.  f.  wiss.  Zool., 
27:238-275,  2  pl. 


3711 


XORTH  AMERICAN  POLYSTOMIDAE—STUNKARD 


EXPLANATION    OF    PLATES 


All  figures   except   those 

of   reconstruction   were  drawn   with   the   aid   of 

a 

camera 

lucida  and  were  made  from  permanent  mounts. 

Abbreviat 

;ions 

used 

a 

acetabulum 

nc 

nerve   commissure 

b 

esophageal  bulb 

0 

ovary 

cm 

circular  muscles 

oc 

eye  spot 

cs 

cirrus   sac 

od 

oviduct 

e 

esophagus 

om 

oblique  muscles 

ed 

excretory  duct 

00 

ootype 

ep 

excretory  pore 

op 

oral  evagination 

9P 

genital  pore 

OS 

oral  sucker 

gc 

genito-intestinal  canal 

ov 

egg 

h 

small  booklets 

p 

postate  gland 

hd 

hermaphroditic  duct 

ph 

pharynx 

i 

intestine 

sp 

septum 

I 

Laurer's  canal 

sv 

seminal  vesicle 

Im 

longitudinal  muscles 

t 

testis 

Is 

lymph  sinus 

u 

uterus 

It 

limiting  membrane 

ud 

uterine  duct 

m 

mouth 

V 

vitellaria 

iiid 

median   dorsal  lymph 

canal 

vd 

vas  deferens 

mg 

Mehlis'  gland 

vg 

vagina 

mo 

marginal  organ 

vl 

vitelline  duct 

mt 

metraterm 

w 

vitello-vaginal  canal 

mv 

median  ventral  lymph  canal 

373]  NORTH  AMERICAN  POLYSTOMIDAE-STUNKARD  93 


PLATE  I 


94  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [374 


EXPLANATION  OF  PLATE 

POLYSTOMA  ORBICULARE 

Fig.  I.  Entire  specimen,  extended,  ventral  view.    X  35. 

Fig.  2.  Hook  from  genital  coronet.    X  225. 

Fig.  3.  Reconstruction  of  genital  apparatus  from  frontal  sections.    X  I3S. 

Fig.  4.  Sagittal  section  thru  caudal  disc.    X  87. 

Fig.  5.  Frontal  section  thru  caudal  disc.     X  7Z- 

Fig.  6.  Sagittal  section  thru  oral  sucker  and  pharynx.     X  140. 


ILLINOIS    BIOLOGICAL   MOXOGRAPHS 


l-OLUME   3 


STUXKARD  NORTH  AMERICAN  POLYSTOMIDAK 


PLATE  I 


375]  NORTH  AMERICAN  POLYSTOMWAE—STUNKARD  95 


PLATE  II 


96  ILLINOIS  BIOLOGICAL  MOXOGRAPIIS  [376 


EXPLANATION  OF  PLATE 

POLYSTOMA    ORBICULARE 

Fig.    7.    Frontal  section.     X  35. 

Fig.    8.     Frontal  section  of  ootype  and  beginning  of  uterine  duct.     X  185. 

Fig.     9.     Frontal    section    of    ootype   and   end    of   right   vitello-vaginal   canal,    five 

sections  ventral  to  Figure  8.     X  185. 
Fig.  10.     Frontal   section,   oiitype   region  of   same   specimen  as  Figures  8  and  9, 
showing  ovary,   uterus,  oviduct,  uterine  duct,  genito-intestinal  canal 
and   vas   deferens.     X  140. 
Frontal    section    showing   vitellaria    and    origin    of    vitelline    ducts    with 

granular  secretion  in  the  cells  and  duct.     X  87. 
Frontal  section  thru  cirrus  sac  at  the  juncture  of  the  shanks  and  roots  of 
the  genital  hooks,  showing  the  genital  papillae  cut  across,  and  a  sec- 
tion of  the  duct  from  the  uterus  at  the  bottom  of  the  figure.     X  250. 
Reconstruction  of  male  genital  apparatus  from  sagittal  sections.     X  140. 
Frontal   section   thru   uterus   showing   embryo  in   stage   of   a  morula-like 
mass  of  cells.     X  700. 


Fig. 

II. 

Fig. 

12. 

Fig. 

13- 

Fig. 

14- 

ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


OK  OU 

STUXKAKD  XORTll   AMKRICAX   POI.VSTOMIDA1-:  PLATP.  II 


XORTH  AMERICAX  POLrSTOMID.iE—STUXK.-lRD 


PLATE  III 


98  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [378 


EXPLANATION  OF  PLATE 

POLYSTOMA   OPACUM 

Fig.  15.     Entire  specimen,  extended,  ventral  view.     X  20. 

Fig.  16.     Reconstruction    of    genital    apparatus    from    toto    preparation    and    cross 

sections.     X  50. 
Fig.  17.     Hook  from  genital  coronet.     X  S50. 
Fig.  18.    Frontal  section  thru  the  anterior  sucker  and  pharynx,  showing  in  section 

nerve  commissures  and  vitellaria.     X  60. 
Fig.  19.     Cross  section  of  body  thru  uterus  and  cirrus  sac.     X  60. 
Fig.  20.     Cross  section  of  body  thru  the  testis.     X  60. 
Fig.  21.     Cross  section  thru  the  anterior  pair  of  bothria.     X  60. 


ILLIXOIS   BIOLOGICAL   MOXOGRAPIIS 


STUXKARD  NORTH  A^rERICAX  POLVSTOMIDAE  PLATE  III 


379]  .\ORTH  AMERICAS  POLYSTOMIDAE—STUXKARD  99 


PLATE  IV 


100  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [380 


EXPLANATION  OF  PLATE 

POLYSTOMA    MEGACOTYLE 

Fig.  22.  Entire   specimen,  ventral   view.     X  27. 

Fig.  22-  Cross  section  of  body  thru  ovary  and  uterus.     X  60. 

Fig.  24.  Cross  section  of  body  thru  vaginae  and  anterior  part  of  the  testis.    X  60. 

Fig.  25.  Cross  section  thru  the  pharynx  near  the  posterior  end.     X  85. 

Fig.  26.  Cross  section  of  seminal  vesicle  and  cirrus  sac.     X  140. 

POLYSTOMA     CORONATUM 

Fig.  27.     Entire  specimen,  ventral  view.     X  27. 


ILLISOIS    niOLOCICAL    MOXOCRAPHS 

2:i 


VOLUME   3 


26 


K 


TV* 


STLXKARO  XORTll  AMF-.RICAX  POLVSTOMIDAE  PLATE  IV 


381]  NORTH  AMERICAN  POLYSTOMIDAE—STUNKARD  101 


PLATE  V 


mZ  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [382 


EXPLAXATIOX  OF  PLATE 

POLYSTOMA     MICROCOTVLE 

Fig.  23.    Entire  specimen,  ventral  view.     X  27. 

Fig.  29.     Ventral  view  of   caudal  disc,  showing  arrangement  of   musculature  and 
hooks.     X  43- 

Poi.YSTOMA     HASSALLI 

Fig.  30.     Entire  specimen,  ventral  view,  ceca  connected  posteriorly.     X  45- 

Fig.  31.     Entire  specimen,  ventral  view,  in  whicli   there  is  no  posterior  connexion 

between   the   ceca.     X  40.  , 

Fig.  Z2.     Reconstruction  of  genital  apparatus  from  frontal  sections.     X  135- 
Fig-  33-     Frontal  section  thru  the  dorsal  part  of  the  uterus,  showing  oral  sucker, 
pharynx,  nerve  commissures,  intestine,  excretory  vesicles  and  ducts, 
vitellaria  and  smaller  tubes  of  the  ootype  region.     X  60. 


ILLIXOIS   BIOLOGICAL    MOXOCR.IPUS 


VOLUME   3 


STL'XKAKD  XUKTli   A.MF-.RICAX   POLVSIdMIDAK 


PLATE  V 


38o]  XORTH  AMERICAN  POLYSTOMWAE—STUKKARD  103 


PLATE  VI 


104 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


1384 


EXPLAXATIOX  OF  PLATE 


Fig. 

34- 

Fig. 

35. 

Fig. 

36. 

Fig. 

37- 

Fig. 

38. 

Fig. 

39. 

Fig. 

40. 

Fig. 

41. 

Fig. 

4^. 

Fig. 

43. 

Fig. 

44. 

Fig.  45- 


Suckers  and  Hooks  of  Various  Species  of  Polystomes 
Polystoiim  orbiculurc.  bothriuiii  from  caudal  disc.     X  140. 
Polystoiiia  orbicularc,  frontal   section   thru   botlirinm.     X  140. 
PolystoiiH}  obknlare,    optical    section     of     bothrinni     showing     cuticnlar 

framework.      X  140. 
'  Polystonta  ol^acttiii,  hook    from    base    of    sucker.     X  165. 
Polystoina  oparnn:,  hook  from  anterior  margin  of  caudal  disc.     X  165. 
Polysloina   tr.iirocotylc,  hooks  of  posterior  margin  of  disc.     X  165. 
Polystoina  o/'acii:}:.   hooks   of   posterior   margin   of   disc.      X  165. 
Polystoina  ir.cgacotylc,   hooks   of   posterior   margin    of   disc.      X  165. 
Polystoina  coronatuiii,   hooks   of   posterior    margin    of    disc.      X  165. 
Polystoina  orbicularc,  hook  from  base  of  sucker.     X  165. 
Polystoina  orbicularc.  frontal  section  thru  a  sucker  illustrating  the  method 

of   operation;    the   e.xtcrnal   zones   are    retracted   with    the   resulting 

protrusion   of  the  basal   part.     X  140. 
Polystonia   intcgerriiiiuiu.  frontal  section   thru  a  sucker  sliowing  type  of 

cuticnlar    framework.     Compare   with    text   and    types    illustrated   in 

other   figures.     X  100. 


lE-LIXOIS   BIOLOGICAL   MOXOCRAPHS 


rOLLME    3 


f^^^'^  y 


STUXKARD  XORTII  AMF.RICAX  POLVSTOMIDAE  PLATE  VI 


385]  NORTH  AMERICAX  ASPIDOCASTRIDAE—STVNKARD  105 


PLATE  VII 


106  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [386 


EXPLANATION  OF  PLATE 

COTYLASPIS  COKERI 

l^ntire  specimen,  extended,  dorsal  view.     X  40. 

Ventral   view    of   entire   specimen   showing   position   of   marginal   organs 

and  divisions  of  the  adhesive  disc.     X  40. 
Reconstruction    of    reproductive    organs    from    frontal    sections.     X  80. 
Cross  section  of  body  at  the  le\el  of  the  ovary  showing  the  ovary,  uterus, 

seminal    vesicle,    intestine,    excretory    ducts,    and    a    follicle    of    the 

vitellaria.     X  87, 
Diagrammatic    representation    of    the    excretory    system    from    a    li\iii}; 

specimen,  dorsal  view.     X  40. 
ObIii|Ue  section  of  body  just  posterior  to  tlie  genital  pores,   showing  in 

section   the  mouth    funnel,   pharyn.x,   cirrus   sac,   uterus,   septum   iiiid 

adhesive  disc.     X  87. 
Pig.  5J.     Entire  specimen,  contracted,  dorsal  view.     X  40. 


Fig. 

46. 

Fig. 

4;. 

Fig. 

48. 

Fig. 

49. 

Fig. 

50- 

Fig. 

51- 

ILLISOIS   BIOLOGICAL   ilOXOGRAPHS 
46 


VOLUME  3 


STUXKARD         NORTH   A.Ml- RICAX   ASriDOGASTRIDAK  PLATE  VII 


387]  NORTH  AMERICAN  ASFIDOGASTRIDAE— STINKARD  107 


PLATE  VIII 


108  ILLIXOIS  BIOLOGICAL  MOKOCRAPllS  [388 


EXPLANATION  OF  PLATE 

COTYLASPIS  COKERI    (EXCEPT  FiCURE  56) 

Fig.  53.  Sagittal  section  thru  the  anterior  end  of  body  showing  musculature,  di- 
gestive and  reproductive  organs.     X  200. 

Fig.  54.     Frontal  section  thru  the  openings  of  the  genital  pores.     X  85. 

Fig.  55.  Section  thru  a  marginal  organ  ;  a  muscle  fiber  is  seen  at  the  left  of  the 
figure  and  on  the  other  side  a  nerve  fibril  passes  to  the  inner  end  of 
the  thick  walled  part  of  the  canal.  In  this  section  the  canal  is  ci!t 
across  and  can  not  be  traced  from  the  bulb  to  the  e.xterior.     X  s8o- 

Fig.  56.     Section  thru  a  marginal  organ  in  Cotylaspis  insignis.     X  580. 

Fig.  57.  I'Vontal  section  thru  tlic  adhesive  disc  showing  arrangement  of  muscula- 
ture.    X  93- 

Fig.  58.  Section  thru  the  anterior  part  of  the  forebody  showing  the  base  of  the 
mouth  funnel,  anterior  part  of  the  pharynx,  nerve  commissure  and 
eye  spots.     X  800. 


ILLIXOIS   BIOLOGICAL   MOSOGRAPHS 


VOLUMn   3 


^  t 


I 

STUXKARI)        NORTH   AM  F.UICAX  ASPIDOC.\STI-:iJ).\i-.         PLAI  i:\lll 


389]        NORTH  AMERIC.-IX  PARAMPHISTOMIDAE—STVXKARD  109 


PLATE  IX 


no  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [390 


EXPLANATION  OF  PLATE 

Alassostoma  magnum 
Fig.  59-    Entire  specimen,  ventral  view.     X  9. 
Fig.  6o.     Cross   section  thru  the  genital   pore  showing  the  terminal  parts  of   the 

cirrus   sac  and  uterus,   the  hemaphroditic  duct,   genital   sinus,   four 

layers  of  muscles  in  the  body  wall  and  the  muscle  lamellae  of  the 

esophageal  bulb.     X27. 
Fig.  61.    Diagrammatic   representation   of    female   genital   apparatus   reconstructed 

from  cross  sections.     X40. 
Fig.  62.     Section  of  the  wall  of  the  intestine.     X36o- 

Fig.  63.    Cross  section  thru  the  oral  sucker  and   the  oral   evaginations.     X  4°- 
Fig.  64.     Cross  section  of  body  at  the  level  of  the  ovary  showing  in  section  the 

ovary,  uterus,  Laurer's  canal,  the  ceca,  vitellaria,  lymph  spaces  and 

excretory  ducts.     X  16. 
Fig.  65.     Cross  section  thru  the  oral  sucker  showing  arrangement  of  muscle  fibers 

and  position  of  the  nuclear  zone.     X  35- 


ILLIXOIS   BIOLOGICAL    MOXOCRAPHS 


y  GLUME    3 


60  .,, 


O  K 

STUXKARD  XOKTII  AMF.RICAX  rARAMPIIISTO.MIDAE  PLATE  IX 


391]        NORTH  AMERICAX  PAR.UIPHISTOMIDAE—STUSKARD         111 


PLATE  X 


112  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [392 


EXPLANATION  OF  PLATE 

Alassostoma  parvum 
Fig.  66.     Entire  specimen,  ventral  view.     X  27. 
Fig.  67.     Cross    section    of    body    posterior    to    the    ovary    showing    coils    of    the 

excretory    ducts.     X  70. 
Fig.  68.     Cross   section  thru  the  posterior  part  of  the  acetabulum  showing  lymph 

spaces  around  the  sucker.     X  70. 
Fig.  69.     Cross  section  a  short  distance  posterior   to  tlie  genital  pore   showing  in 

section,  the  uterus,  the  cirrus  sac,  and  above  the  latter  organ  three 

loops  of  the  seminal  vesicle.     X  70. 
Fig.  70.     Cross  section  of  esophageal  bulb  with  clusters  of  surrounding  cells.  X  70. 
Fig.  71.     Cross  section  of  body  thru  the  genital  pore  showing  hermaphroditic  duct, 

cirrus  sac,  lymph  spaces  and  the  character  of  the  parenchyma.     X  9°. 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 
67 


VOLUME  3 


STUXKARD         XORTll  A.MliRICAX  PARA.MPHISTO.MIDAR         PLATE  X 


393]        XORTH  AMERICAX  PARAMPHISTOMIDAE—STUXKARD         113 


PLATE  XI 


114 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


[39+ 


Fig. 

-2. 

Fig. 

73- 

Fig. 

74- 

Fig. 

75- 

Fig. 

76. 

Fig. 

'/■ 

Fig.  78. 


EXPLANATION  OF  PL.\TE 

Zygocotyle  ceratos.\ 
Entire    specimen,   ventral   view.     X  n- 
Cross  section  of  esophageal  bulb,  showing  the  arrangement  of  the  muscle 

fibers.     X  45-     Compare  with  Figures  60  and  70. 
Cross  section  of  body  thru  the  origin  of  the  oral  evaginations.     X  45. 
Sagittal  section  thru  the  anterior  part  of  the  bodj-  showing  oral  sucker, 

an  oral  evagination  and  the  anterior  part  of  the  esophagus.     X  45- 
Sagittal  section  of  posterior  part  of  body  thru  one  side  of  the  acetabulum. 

X27. 
Sagittal  section  of  the  posterior  part  of  the  body  near  the  median  line, 

showing  the  ovary,  eggs  in  the  uterus,  Laurer"s  canal,  and  the  shape 

of   the   acetabulum.     X  27. 
Sagittal  section  thru  the  body  one  section  at  the  side  of  the  genital  pores 

showing   the   folded   wall   of   the   uterus   and   the    ejaeulatory   duct 

which  in  this  species  is  without  a  cirrus  sac.     X  136. 
Representation  of  the  sagittal  section  thru  the  openings  of  Laurer"s  canal 

and  the  e.xcretory  vesicle.     X  90- 


ILLIXOIS   BIOLOGICAL   MOXOCR.IPHS 


STUXKARI)  XORTll  AMERICAN  PARAMrillSTOMIDAK  PLATE  XI 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 

Vol.  in  ApnU917  No.  4 

Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate  School  bh 

THE  University  of  Illinois 


Copyright,  1917 

By  THE  University  of  Illinois 

Distributed  June  30,  1917 


COLOR  AND 

COLOR-PATTERN  MECHANISM 

OF  TIGER  BEETLES 

WITH  TWENTY-NINE  BLACK  AND 
THREE  COLORED  PLATES 


VICTOR  E.  SHELFORD 


TABLE  OF  CONTENTS 


PAGE 

Introduction 5 

Materials  and  methods  - 6 

Analysis  of  Color  Patterns  ~ 13 

Color  Patterns  and  Elytral  Structures  13 

The  Color  Pattern  Plan  19 

Color  Pattern  and  Pigment  Development  21 

Experimental  Modification  of  Patterns  38 

Geographic  Variation   of   Patterns  - 40 

Colors  of  Tiger  Beetles  46 

Causes  of  Colors  - ■■ 46 

Ontogeny  of  Color  47 

Relation  of  Ontogenetic  Stages  to  Geographic  Races 49 

Geographic  Variation  in   Color  52 

Experimental  Modification  of  Color  _ 55 

Relation  of  Colors  and  Color  Patterns  to  Climate  56 

Geographic  Center  of  the  Group  on  the  Basis  of  Patterns 57 

General  Discussion   .- - 58 

Pattern  Tendencies  - 58 

Bearing  of  the  Color  Pattern  Mechanism  on  Orthogenesis 63 

Bearing  of  the  Pattern  ^Mechanism  on  the  Biogenetic  Law 65 

Summary  of  Conclusions  „ -- 66 

Patterns    ..._ - 66 

Color - - 67 

Geography  67 

Bibliography    .- 68 

Explanation  of   Plates  "i 


399]  COLORS  OF  TIGER  BEETLES—SHELF ORD 


INTRODUCTION 

In  the  analysis  of  characters  made  the  basis  of  studies  of  variation, 
orthogeuetie  trends,  experimental  modification  and  heredity,  noteworthy 
advantages  are  associated  with  the  study  of  large  groups  of  species 
in  which  divergence  and  modification  have  proceeded  in  various  direc- 
tions. The  material  should  be  plastic  so  that  the  laws  governing 
response  in  characters  can  be  determined.  The  ontogeny  of  the  char- 
acters should  be  of  such  a  character  as  to  show  the  general  ground 
plan  of  the  system  and  its  relation  to  the  existing  adult  characters  and 
their  variations.  It  is  further  desirable  to  be  able  to  breed  the  organ- 
ism, segregate  pure  lines,  and  cross  various  species.  There  is  a  strong 
tendenej'  of  late  years  to  regard  the  breeding  and  the  breeding  results 
as  superior  to  the  other  attempts  at  character  analj'sis.  This  has  pro- 
ceeded to  such  an  extent  without  adequate  physiological  analysis  that 
one  writer  (Riddle,  1909)  designated  the  method  of  cross  breeding  "the 
mixing  of  unknowns".  The  primary  object  of  this  paper  is  to  show 
the  nature  of  the  color  and  color-pattern  mechanism  of  the  elytron. 

In  the  matter  of  qualifications  of  material  the  tiger  beetles  are 
admirably  adapted  to  all  the  needs  enumerated  above,  but  since  one 
year  at  least  and  normally  two  are  necessary  for  a  generation,  only 
a  few  single  generations  have  been  bred.  For  this  reason  the  idea  of 
breeding  them  was  abandoned.  It  is  also  a  purpose  of  this  paper  to- 
show  that  breeding  is  not  the  only  method  by  which  adequate  analysis 
can  be  reached,  i.e.,  unless  the  laws  governing  heredity  are  a  system 
entirely  a  part  from  those  governing  the  modification  of  parts  during 
ontogeny  and  the  normal  course  of  A'ariation,  which  seems  to  be  the- 
tacit  assumption  of  various  students  of  heredity  in  the  not  too  distant 
past. 

I  shall  indicate  further  that  orthogenetic  tendencies,  if  directive 
tendencies  are  to  be  so  named,  are  numerous  and  in  a  large  series  of 
species  present  a  confusing  set  of  groups  wliieh  are  excessively  com- 
plicated and  reduced  to  any  simple  system,  as  claimed  bj^  Eimer  and 
von  Linden  for  Lepidoptera  or  for  a  limited  number  of  species  by 
Wlntman,  with  difficulty.  Still,  large  tendencies  with  numerous  minor 
ones  within  them  may  be  detected.  It  will  be  shown  that  the  laws 
governing  the  modification  of  patterns  apply  alike  to  general,  probably 
liereditary   tc.'^deiicies   a;ii!   det:;il''d    r,:.spc:t  y.i   under  e.\j*:'rijii.':iiKl    co;)- 


6  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [400 

ditions.  It  will  be  shown  that  biogenetic  law  must  be  applied  with, 
caution  and  is  not  of  such  broad  application  as  is  held  iu  some  quar- 
ters,  being  inapplicable  to  various  characters  altogether. 

The  brilliant  colors  of  the  group  are  due  to  physical  phenomena 
determined  by  Professor  Llichelson,  and  leave  no  place  for  the  bioge- 
netic law  iu  connection  with  the  development  of  color  during  ontogeuj'. 
It  will  be  shown  further  that  color  is  closely  correlated  with  general 
physiological  condition  and  is  modifiable  by  conditions  which  affect 
general  metabolism.  The  results  here  pi'esented  are  based  on  several 
years  of  observation. 

In  1903  the  writer  undertook  a  study  of,  variation  of  the  tiger 
beetles.  The  work  here  presented  is  the  outgrowth  of  this  beginning, 
and  indeed  includes  some  small  portions  regarding  color  patterns  that 
were  written  in  that  year.  The  work  has  been  prolonged  for  many 
reasons,  but  chief  of  these  was  the'  very  large  number  of  species  in 
the  group  and  the  fact  that  an  adequate  understanding  of  the  mate- 
rial could  not  be  attained  without  consulting  many  large  collections. 
Further,  the  experimental  results  obtained  in  1906  demanded  a  first- 
hand study  of  the  variations  of  the  species  concerned  and  their  natu- 
ral habitats.  The  accumulation  of  material  and  data  was  not  com- 
pleted until  1911.  Some  of  this  had  to  be  studied,  drawings  made,  etc., 
which  with  numerous  other  duties  and  enterprises  iiuder  way  made 
necessary  much  time  to  put  it  into  the  present  form. 

A  family  with  i^pwards  of  1300  species  of  which  more  than  600 
are  in  one  genus  and  with  characters  which  can  be  studied  and 
analyzed,  appeared  to  afford  material  which  was  sufficiently  promis- 
ing to  justify  delay.  In  the  fourteen  years  that  have  elapsed  since 
the  problem  was  first  undertaken  at  the  suggestion  of  Dr.  C.  B.  Dav- 
enport, the  attention  of  biologists  has  shifted  from  variation,  which 
was  then  the  chief  topic  of  interest,  to  experimental  modification  of 
characters,  and  finally  to  the  methods  of  modern  genetics.  Various 
men  have  made  numerous  suggestions  regarding  the  work,  but  in  its 
final  preparation  the  writer  has  been  able  to  use  only  a  few  of  them 
in  a  general  way,  and  an  attempt  is  made  to  present  tlie  facts  and 
conclusions  growing  out  of  the  material  as  simply  as  possible. 

MATERI.\LS  AND   METHODS 

The  material  which  has  been  used  as  the  basis  of  this  work  has 
consisted  of  collections  in  the  family  Cicindelidae  of  the  world,  exten- 
sive collections  of  several  North  American  species,  repeated  year-to-year 
collections  of  a  few  species  in  Illinois  and  Indiana,  series  of  observations 
on  the  ontogenv  of  color  in  a  small  number  of  North  American  species. 


401]  COLORS  OF  TIGER  BEETLES— SHELFORD  7 

and  experimental  modification  of  a  number  of  species  which  has  assisted 
in  the  analysis  of  the  color  patterns. 

The  collections  studied  have  covered  most  of  the  species  of  the 
family,  which  is  divided  into  several  tribes  by  W.  Horn  in  the  Genera 
Insectorum  (1915).  The  subfamilies  herein  named  were  in  part  given 
as  families  in  the  Systematischer  Index  of  the  same  author  (1906), 
in  which  he  presented  a  preliminary  list  of  the  species  which  he  later 
published  in  the  Genera  Insectorum.  Accordingly,  in  my  previous  papers 
on  the  subject  (1906,  1908,  1912.  1914,  1915)  the  "Index"  -was  followed 
almost  entirely  in  the  matter  of  nomenclature  and  order  of  arrange- 
ment. 

The  groups  represented  in  the  family  as  outlined  in  Genera  Insect- 
orum are  as  follows : 

Subfamily  Ctenostomini  (tree  dwellei's)  Number  of  species 

Pogonostoma;  Madagascar 32 

Ctenostoraa ;  tropical  America 45 

Subfamily  Collyrini  (nearly  all  tree  dwellers) 

Tricondyla;   India " 27 

Collyris;  Oriental  region __ 104 

Subfamily  Mantichorini  (ground  dwellers) 

IMantiea ;  Africa _ 1 

Mantichora  ;  Africa 5 

Subfamily  Megaeephalini  (ground  dwellers) 

Platychila ;  South  Africa....  1 

Pycnochila ;  South  America  1 

Amblyehila;  Western  U.  S.  A.  2 

Omus;  Western  U.  S.  A 4 

Aniaria :  Northeastern  South  America _ 1 

Megacephala ;  southern  U.  S.  to  Argentine,  Africa, 

Arabia,  Persia,  Australia ......_ 68 

Oxyehila ;  middle  America 25 

Pseudoxychila :  Andes.  Costa  Rica  to  Bolivia 1 

Chiloxia ;  Andes  of  Ecuador  to  Bolivia 1 

Eucallia ;  Andes  of  Ecuador  and  Columbia 1 

Subfamily  Cicindelini ;  ground  dwellers 

Dromiea ;  southern  half  of  Africa 82 

Prothyma  ;  Africa,  Madagascar,  Asia,  and  the  Malay 

Archipelago  _ 50 

Dilatotarsa ;  Malay  Archipeligo 1 

Caledonomorpha ;  New  Guinea 1 

Di.stipsidei'a ;  Australia  and  New  Guinea 8 

Caledonica ;  New  Guinea 9 


8  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [402 

Nickerlea  ;  Australia _ 2 

Rhysopleura  ;   Australia 1 

Euprosopus;  Brazil 2 

Langea;  Peru 1 

Iresia;  coutinental  tropical  America 8 

Tlierates ;  ilalay  Archipelago 33 

Odontoehila;     South    America,    Malay    Pen.    and 

Islands  75 

Prepusa ;  South  America) 3 

Oxygonia ;  South  America 15 

Opistheneentrus  :  Brazil 1 

Cieindela ;  world-wide  distribution  686 

Eurymorpha;  Africa _ _ 1 

Apteroessa;   India 1 

1299 
The  group  contains  some  35  genera  and  upwards  of  1300  species 
and  subspecies.  In  the  figures  above  the  subspecies  of  Cieindela  number- 
ed in  Roman  in  Horn's  Genera  Insectontiu  list,  -which  number  55,  are 
included,  but  subspecies  numbering  more  than  8  in  llegacephala  alone, 
and  several  in  other  genera,  are  not  included. 

There  are  very  few  of  these  1300  races  which  the  writer  has  not 
seen  in  some  one  of  the  particularlj^  numerotis  and  complete  collections 
studied.  Those  studied  quite  completely  are :  British  Museum  of  Natural 
History ;  Hope  Collection,  Oxford  University ;  Cambridge  University ; 
Private  Collection  of  Mr.  Basil  G.  Nevinson,  London ;  Private  Collection 
of  Dr.  Walther  Horn,  Berlin;  Zoologisches  Museum,  Berlin;  Private 
Collection  of  Doctor  Gestro,  Genoa ;  Jardin  des  Plantes,  Paris ;  Museum 
of  Comparative  Zoology,  Cambridge,  ^Massachusetts ;  United  States 
National  Museum ;  Philadelphia  Academy  of  Science  :  American  Museiuu 
of  Natural  History,  New  York ;  and  the  University  of  Chicago  collection 
including  an  old  collection  once  the  property  of  John  Akhurst,  Brook- 
lyn, several  purchases  from  Hermann  Rolle  of  Berlin,  and  the  material 
secured  by  exchange  for  other  species  in  the  Akhurst  collection,  and 
material  purchased  and  collected  for  the  writer  by  the  University,  and 
specimens  collected  on  the  excursions  supported  by  the  University.  In 
addition  to  this  the  writer  secured  a  collection  of  exotic  material  from 
Mr.  John  D.  Sherman  in  exchange  for  Dytiscidae  and  numerous  speci- 
mens by  exchange  and  gift  from  numerous  American  and  foreign  collect- 
ors. Of  the  few  species  not  seen  several  are  represented  in  figures  which 
show  the  color  patterns. 

Many  of  the  drawings  presented  are  from  the  collections  in  ques- 
tion ard  arp  appropriately  designated  in  the  groups  of  figures  in  th" 


403] 


COLORS  OF  TIGER  BEETLES— SHELFORD 


succeeding  pages.  The  meaning  of  the  designations  is  as  follows: 
B,  British  Museum ;  C,  Cambridge  University ;  D,  Berlin ;  G,  Gestro ; 
H,  W.  Horn,  Berlin ;  M,  U.  S.  National  LIuseum ;  N,  Xeviusou ;  0,  Oxford 
University;  P,  Paris;  S,  Shelford;  U,  University  of  Chicago. 

While  none  of  the  patterns  of  the  genera  other  than  Ciciudela  are 
of  a  type  differing  from  the  general  plan  of  the  Ciciudela,  patterns  are 
very  often  wanting  or  veiy  simple,  such  as  the  simple  cross  bands  in 
Collyris.  In  course  of  the  examination  of  the  several  collections  named, 
a  great  abuudance  of  variation  has  beeu  noted  in  some  of  the  commoner 
representatives  of  the  groups,  not  only  of  Ciciudela  but  others  also. 

The  taxonomic  arrangement  of  Ciciudela  by  Doctor  Horn  in  the 
Genera  Insectorum  is  especially  fortunate.  He  has  arranged  the  species 
into  a  niimber  of  groups  on  the  basis  of  the  distribution  of  hairs  on  the 
head,  thorax,  abdomen,  tarsi,  labrum,  and  of  other  structural  characters, 
but  without  reference  to  color  patterns.  He  gives  174  groups  apparently 
not  duplicated  in  the  different  regions  and  16  represented  in  more  than 
one  zoogeographic  region  by  the  same  or  closely  related  species.  These 
174  groups  are  distributed  as  follows :  Ethiopian  region,  34 ;  Oriental  , 
region,  48 ;  Australian  region,  22 ;  Palearotic  region  which  he  extends 
to  include  China,  20;  Nearctie  region,  24;  Neotropical  region,  26.  The 
groups  foimd  in  more  than  one  region  and  which  are  counted  in  the  one 
with  most  species,  are  as  follows : 

Table  I 
Showing  the  Number  of  Species  in  Regions  by  Groups  as  Designated  by  a 
Common  Species 


singularis  Chd 

melancholica  Fab 

doncgaleiisis  Chd 

iiilotica  Dj 

grrmanica  L - 

foveolata  Schm 

laetescripta  Mtsch 

10  guttata  Fab 

striolata  Ulig 

discrete  Schm 

seiniciiicta  Br 

brcfispoiiosKsW'. Horn 

carthagena  Dej 

argentata  Fabr 

irifasciafa  Fabr 

macrocnema  Chd 


10  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [404 

111  the  above  list  species  occurring  in  two  are  counted  in  botli.  So 
far  as  practicable  these  pilosity  groiii3S  have  been  considered  in  working 
up,  arranging,  and  discussing  the  patterns. 

Considerable  change  has  been  made  in  the  nomenclature  and  arrange- 
ment of  species  in  the  Genera  Inseetorum  as  compared  with  Doctor 
Horn's  Index.  The  paper  had  progressed  so  far  with  the  Index  as  a 
tasis  that  it  was  thought  not  to  be  practicable  to  change  it  to  agree  with 
the  newer  work. 

The  extensive  collection  of  North  American  species  belong  to  the 
first  group  in  Horn's  series  for  the  Nearctic  region.  This  group  includes 
tranqucharica  and  will  be  referred  to  as  tlie  Tnniquebarica  Group.  These 
are  cliaracterized  as  follows:  The  four  anterior  trochanters  have  fixed 
hairs,  cheeks  naked,  or  with  isolated  hairs,  clij^eus  often  hairy.  Frons 
mth  discoidal  or  supraorbital  hairs ;  median  portion  of  the  frons  never 
proportionately  supplied  with  more  or  less  short,  close  Ij'ing,  do^vnward 
directed  hairs ;  frons  never  hairy  above  the  antenual  insertion.  The  disc 
of  the  middle  frons  is  often  hollowed  out  or  sharply  separated  from  the 
fore  frons  by  its  steepness.  The  first  antennal  segment  is  often  thickly 
covered  with  outstanding  hairs.  The  pronotum  has  at  least  rudiment- 
ary hairs,  often  circumdiscally  and  discally  hairy ;  hairs  often  long  and 
fine  and  never  decumbent  except  when  very  numerous ;  free  anterior  and 
posterior  border  of  the  pronotum  not  hairy.  The  prosternum  is  always 
naked.  The  lateral  portion  of  the  breast  is  always  thickly  covered  with 
hairs.  The  hind  border  of  the  femur  and  sometimes  the  foreborder  also 
covered  with  fine  short  decumbent  hairs ;  hook-formed  hairs  never  pres- 
ent; hairs  on  the  hip  and  superorbital  border  most  numerous.  This 
group  stands  in  close  relation  to  the  European  group  to  which  campestris 
belongs.  The  main  group  includes  formosa,*  venusta,  limbata,  purpurea* 
ancosisconensis,  duodecemguttata,*  hirticollis*  latesignata,  traitquchar- 
ica*  tenuicincta,  bellissima,  longilahris,  eureka,  oregoiia,  senilis,  iviUi- 
stoni,  fulgida,  pidchra,  pimeriana,  scutellaris*  In  addition  to  this, 
collections  were  made  of  C.  sexguttata  which  stands  in  a  group  by  itself. 
Those  starred  were  studied  especially.  Collections  of  these  species 
representing  complete  catches  were  supplied  by  C.  S.  Brimley,  E.  G. 
Smyth,  C.  A.  Frost,  L.  H.  Joutel,  Rev.  J.  C.  Varren,  and  Dr.  C.  F. 
Adams.  Collections  were  made  by  the  writer  in  various  parts  of  the 
United  States. 

The  species  about  Chicago,  especially  scutellaris,  were  collected 
through  the  year  from  the  same  loealit.y  with  a  view  to  getting  the 
seasonal  variation  of  the  species  and  any  variation  from  generation  to 
generation. 


405]         COLORS  OF  TIGER  BEETLES— SHELFORD  11 

The  color  outogeuy  woi'k  was  done  on  material  dug  in  the  larval 
stage  at  Gleiicoe,  Illinois  (C  limbalis)  ;  at  Gary,  Indiana,  (C  tranque- 
iarka)  ;  at  iliUer,  Indiana  (C  lecontei)  ;  at  Lyons,  Illinois  (C.  pur- 
purea) ;  at  East  Chicago,  Indiana  (C  repanda) ;  Chicago  vacant  lots 
(C.  puncfuhifa)  ;  and  Suman,  Indiana  (C  stxguttata).  These  larvae 
■were  reared  in  a  greenhouse  in  which  the  temperatiu'e  was  about  4  to  8 
degrees  C.  higher  than  the  out-door  soil  temperature.  This  accelerated 
the  appearance  only  a  little  and  did  not  show  modification  of  color  or 
pattern.  The  larvae  were  reared  in  sand,  either  in  cylindrical  lamp 
chimneys,  setting  in  screen  bottomed  boxes  or  in  screen  bottomed  boxes. 
"VSTien  the  majority  of  larvae  and.  pupated  all  were  removed  to  small 
square  watch  glasses,  lined  with  filter  paper  and  moistened  with  2% 
HjOo.  These  were  piled  up  so  as  to  cover  each  other  and  kept  in  a 
cool  room,  and  watched  closely  to  secure  as  many  as  practicable  at  the 
time  of  emergence.  The  elytral  material  was  nearlj-  all  killed  in  a  picro- 
sulfurie  acid  killing  fluid  and  cleared  and  mounted  in  balsam,  but 
some  was  preserved  in  glycerine  jelly  direct  with  good  results.  They 
were  preserved  at  different  intervals  after  emergence. 

The  material  for  experiments  was  collected  from  the  same  places 
as  that  for  ontogeny  study  and  was  subjected  to  high  and  low  tem- 
peratures in  an  apparatus  to  be  described  later. 

The  writer  is  indebted  to  Dr.  C.  B.  Davenport,  the  late  Professor 
C.  0.  Whitman,  Professor  C.  M.  Child,  and  Professor  W.  L.  Tower 
for  suggestions  during  the  first  four  years  of  the  work  (1903-1907). 
He  is  further  indebted  to  the  University  of  Chicago  for  funds  amount- 
ing to  .$400  and  to  Professor  and  Mrs.  F.  R.  Lillie  for  funds  amounting 
to  $200  to  cover  expenses  connected  with  the  study  and  collection  of 
the  group.  The  Graduate  School  and  Department  of  Zoolog.v  of  the 
Univesity  of  Illinois  provided  for  later  stages  of  the  work. 

Acknowledgments  are  due  Jliss  Annette  Covington  for  making  the 
water  color  drawings  of  the  ontogenetic  stages  and  the  other  changes 
in  color  during  the  life  history.  Mr.  K.  Toda  made  the  drawings  of 
the  geographic  races  shown  in  color  and  also  the  stippled  drawings  of 
ontogeny. 

The  writer  is  especially  indebted  to  Professor  A.  A.  Jliclielsou 
of.  the  University  of  Chicago  for  making  physical  determinations  of 
the  colors  of  Cieindela.  The  courtesies  connected  with  the  study  of 
collections  were  numerous.  The  following  were  especially  kind  in 
facilitating  the  study  of  collections  in  their  charge :  Dr.  Samuel  Hen- 
shaw,  Museum  of  Comparative  Zoology ;  Dr.  Sehwarz,  U.  S.  National 
Muse'am ;  Dr.  Henry  Skinner,  Philadelphia  Academy ;  'Mr.  William 
Beutenmuller.  American  iluseum;  Mr.  Gilbert  I.  Arrow  and  Mr.  C. 
J.  Gahan,  the  British  Museum;  Professor  Poulton  and  the  late  Mr. 


12  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [406 

R.  Shelford,  Hope  Collections,  Oxford ;  Pi'ofessor  David  Shai'pe,  Cam- 
bridge ;  Professor  Kolbe,  Berlin ;  Mr.  P.  Lesne,  Paris. 

The  following  permitted  me  to  study  their  private  collections  with 
a  considerable  loss  of  time  and  attention:  Dr.  Walther  Horn,  Berlin; 
Mr.  Basil  G.  Neviusou,  3  Tedworth  Square,  Lojidon :  Mr.  Gestro, 
Genoa. 

A  considerable  number  of  men  whose  names  appear  below  gave 
me  data  on  the  distribution  of  the  species  in  their  collections,  loaned 
or  presented  specimens,  or  did  similar  service  through  making  exten- 
sive collections  which  were  exchanged.  For  this  I  am  debtor  to  Messrs. 
C.  F.  Adams,  C.  N.  Ainslie,  Geo.  G.  Ainslie,  E.  M.  Anderson,  A.  W. 
Andrews,  Germain  Beaulieu,  Biederman,  Wm.  Beutenmuller,  Albert 
L.  Barrows,  C.  S.  Brimley,  T.  C.  Brues,  T.  D.  A.  Cockerell,  I.  W. 
Cockle,  Norman  Criddle,  F.  F.  Crevcoeur,  C.  C.  Deam,  G.  M.  Dodge, 
Edwin  H.  Edwards,  J.  D.  Evans,  S.  A.  Forbes,  E.  P.  Felt,  E.  D.  Har- 
ris, R.  V.  Harvey,  G.  W.  Herrick,  H.  R.  Hill,  J.  S.  Hiue,  A.  D.  Hop- 
kins, W.  Horn,  James  Hunsen,  S.  A.  Johnson,  James  Jolinson,  W. 
Knans,  Chas.  W.  Leng,  H.  P.  Lodiug,  D.  E.  Lantz,  W.  ^Macintosh, 
G.  P.  Mackenzie,  L.  E.  Marmont,  A.  L.  Melander,  F.  W.  Nuuenmacher, 
W.  E.  Rumsey,  L.  E.  Rieksecker,  A.  G.  Ruthven,  Franklin  Sherman, 
H.  F.  Snow,  E.  G.  Smyth,  Tom  Spalding,  Chas.  Stevenson,  T.  B.  Sy- 
mons,  H.  B.  Walden,  H.  F.  Wickliam.  T.  N.  Willing,  R.  S.  Woglum, 
R.  H.  Wolcott,  E.  0.  Wooton,  E.  C.  VauDyke,  E.  P.  Venables,  S.  S. 
Visher. 


407]  COLORS  OF  TIGER  BEETLES— SHELFORD 


ANALYSIS  OF  COLOR  PATTERNS 

COLOR  PATTERNS  AND  ELYTRAL  STRUCTURES 

In  the  Cicindelidae  usually  onlj'  the  elytra  have  color  patterus. 
These  are  merely  sack  like  outgrowths  supplied  vAih.  nerves,  trachea, 
and  blood  spaces.  The  cutieular  covering  is  in  two  layers;,  the  outer 
portion  is  a  hard  and  relatively  homogeneous  layer  known  as  the  primary 
cuticitla  and  on  the  upper  side  is  usually  characterized  by  the  presence 
of  saucer-shaped  depressions,  somewhat  hexagonal  in  form,  fitting  to- 
gether with  common  rims.  These  rims  usually  correspond  to  the  posi- 
tions of  the  points  of  contact  of  the  hypodermal  cells  and  accordingly 
each  cup  corresponds  to  a  cell  (Packard,  1900  text).  Some  forms  in 
the  family,  e.  g.,  the  Tetraehas  and  the  Amblychilas  do  not  have  these 
cups;  the  surface  is  smooth.  In  certain  areas  the  primary  cuticula  is 
pigmented  and  in  certain  areas  clear  and  transparent.  This  gives  the 
color  pattern.  Some  species  are  almost  entirely  pigmented ;  some  entirely 
without  pigment.  Beneath  the  primary  cuticle  is  the  secondary  cuticula 
which  is  laid  down  in  successive  layers  during  the  life  of  the  individual 
and  in  the  forms  like  Ambli)chila  cylindriformis,  and  Phaeoxantha 
klugi  is  essentially  uniform  in  character.  It  contains  some  spaces,  prob- 
ably pore  canals,  which  are  empty  of  cell  contents  except  for  the  layer 
in  actual  contact  with  the  cells.  A  few  of  these  pore  canals  can  be 
detected  in  the  secondary-  cuticula  of  Tctracha  Carolina.  In  Cieindela 
the  secondary  cuticula  beneath  the  pigmented  areas  of  the  elytron  is 
clear  and  transparent  and  entirely  free  from  the  "pore  canals"  and 
interlamellar  spaces,  while  beneath  the  unpigmented  areas  it  is  full  of 
the  "pore  canals"  and  large  interlamellar  spaces,  and  these  having 
been  left  empty  by  the  retreat  of  the  cells  from  the  successive  layers; 
they  give  the  effect  of  a  white  or  straw  color  depending  upon  the  color 
of  the  secondary  cuticula  itself.  In  these  regions,  beneath  the  unpig- 
mented primarv  cuticula,  it  is  about  twice  as  thick  as  beneath  the 
pigmented  parts  (Fig.  1,  PI.  I).  The  color  pattern  may  accordingly 
be  described  in  terms  of  pigment  and  lack  of  pigment,  the  so-called 
markings  being  without  pigment. 

The  two  walls  of  the  sac-like  elytron  are  held  together  by  chitinous 
pillars  or  columns  which  in  the  adult  appear  in  cleared  elytra.  The 
different  lavers  of  cuticula  show  here  as  rings  around  the   original 


14  ILLISOIS  BIOLOGICAL  MOXOGRAPHS  [408 

central  spindle  (Shelford  1915:243,  Fig.  1).  In  the  Ciciudelidae  the 
ehitinous  columns  are  not  arranged  in  any  very  defiiiite  manner  but  in 
some  eases  they  retain  their  pigment  within  areas  that  are  not  othei-- 
wise  pigmented. 

Hairs  which  in  a  primitive  insect  usually  cover  the  wing  entirely 
are  present  in  nearly  all  tiger  bettle  elytra.  In  the  ilautiehoras,  observed 
representative  of  the  Pogonostomidae,  and  one  of  the  Megacephalidae, 
Mcgacephala  {Tetracha)  aequinoctialis,  the  elytra  are  more  or  less  com- 
pletely and  uniformly  covered  with  small  hairs.  Under  the  microscope 
the  hairs  may  be  located  on  the  pigmented  area  of  the  elytra  by  the 
light  area  which  is  produced  by  the  thin  cuticula  at  the  base  of  each 
hair.  Hairs  appear  on  the  whole  to  be  less  common  in  the  unpigmented 
areas  and  when  present  usually  are  surrounded  by  a  narrow  rim  of 
pigmented  cuticula.  Hairs  occur  in  i^ractically  all  groups,  thoiigli  they 
have  been  lost  from  the  majority  except  for  a  few  at  the  base  of  the 
elytron  and  scattered  along  the  tracheae  ( Shelf ord,  1915:243,  Figs. 
1  to  3).  These  are  present  in  Cicindela  and  are  sho's\ai  by  small  circles 
in  figures  2  to  29,  plate  I  to  III. 

The  elj'tra  of  many  species  are  marked  with  jjits.  Close  examin- 
ation under  the  microscope  with  both  transmitted  and  reflected  light 
shows  that,  in  the  majority  of  cases,  the  pits  are  over  the  center  of  the 
ehitinous  columns  and  bear  no  relation  to  rudimentary  hairs  as  Dr.  W. 
Horn  has  suggested.  I  have  seen  uo  pits  that  would  appear  to  represent 
rudimentary  liairs  though  they  may  occur. 

There  are  sometimes  thickenings  running  lengthwise  of  the  elytron 
as  iu  Domiea  (Shelf ord,  1915:  Figs.  35  and  36).  While  these  thicken- 
ings run  parallel  with  the  trachea,  they  are  usually  between  ratlier  than 
coincident  with  them,  except  in  Caledonica  (Fig.  25).  There  are,  how- 
ever, some  thickenings  on  the  under  side  of  the  elytra  of  most  species 
which  correspond  in  a  general  way  to  veins  (particularly  in  Mantichoi'a ) . 
The  outer  and  inner  margins  of  the  elytra  are  always  thickened  and 
resemble  veins,  almost  invariabl.y  containing  tracheae.  The  subcosta 
usually  follows  tlie  costa  very  closely  at  the  base  of  the  elytron  but  just 
behind  the  middle  it  turns  inward  away  from  the  margin  in  a  vein  like 
thickening.  The  radius  is  in  a  distinct  thickening  of  the  elytron  which 
proceeds  from  the  base  for  a  short  distance.  This  is  very  constantly 
present.  Aside  from  this  nothing  comparable  to  veins  is  present  but  the 
rows  of  ehitinous  columns  are  often  so  arranged  so  as  to  give  distinct 
and  direct  spaces  running  the  length  of  wing.  These  are  occupied  by 
the  principal  tracheae.  In  some  cases  the  spaces  appear  very  clearly  on 
the  under  side  of  the  elytron  and  in  JMautichora  there  are  distinct  ridges 
over  them  which  have  every  appearance  of  veins. 


409]  COLORS  OF  TIGER  BEETLES—SHELFORD  15 

The  elytral  tracheation  of  the  Cieindela  has  been  observed  by  the 
writei"  in  about  one  hundred  species.  The  elytra  of  the  newly  emerged 
^magoes  of  ten  North  American  species  have  been  studied  in  some  detail. 
Nearly  all  the  common  North  American  species  and  about  fifty  exotic 
species  have  been  studied  in  less  detail  by  mounting  dried  elytra  in  hot 
Canada  balsam  containing  little  or  none  of  the  usual  solvents.  The 
main  tracheal  trunks  and  some  of  the  branches  remain  clearly  visible 
in  such  mounts  for  several  hours. 

In  terms  of  the  system  of  classification  proposed  by  Comstoek  and 
Needham,  the  usual  tracheae  present  (Figs.  18  and  21,  PI.  II)  are 
the  costa  {Co)  which  branches  near  its  distal  end,  and  subcosta  (S) 
which  lies  close  to  the  costa  on  the  outer  edge  of  elytron ;  the  radius  {R) 
and  media  (.1/)  which  lie  in  the  medium  portion  of  the  elytron;  the 
cubitus  (C»)  which  lies  along  the  suture,  and  {A)  the  anal  rudiment 
which  lies  next  to  the  scutellum. 

The  six  tninks  common  in  insects  are  represented  in  but  two  genera 
(Aniblychila  and  JIantichora),  which  have  rudimentary  wings  and 
specialized  elytra  fastened  together  in  the  adult  (Shelfoi'd,  1915). 
These  trachea  are  demonstrated  in  the  adult  dried  elytra  without  any 
difficulty.  In  Omus,  which  is  closely  related  to  Amblychila,  the  radius 
and  media  have  disappeared  except  for  rudiments.  The  cubitus  is  the 
principal  trachea.  With  the  exception  of  Omus  and  Amblychila  it  is 
the  anal  that  has  degenerated  farthest.  Collyris  was  never  veiy  satis- 
factory for  study,  but  it  appears  that  the  cubitus  is  reduced  and  the 
anal  wanting.  In  Platychila  pallida  (Shelford,  1911:  Fig.  7)  the  com- 
monest type  of  tracheation  of  the  family  and  probably  among  the  most 
generalized,  so  far  as  the  first  four  trachea,  are  concerned,  is  shown.  The 
anal  is  much  reduced. 

The  munber  of  small  branches  and  cross  connections  is  large  and 
too  variable  to  be  correlated  with  other  specific  characters  or  with  color- 
pattern  characters.  Figures  already  published  (Shelford,  1913:  Figs.  10 
to  19)  illustrate  this  fact.  The  two  elytra  of  an  individual  show  a  mark- 
ed difference.  It  is  evident  then  that  only  the  main  trunks  are  at  all 
constant.  The  costal  branch  at  the  center  the  posterior  third  of  the 
elytron  at  the  beginning  of  the  curve  is  very  characteristic  of  Cieindela 
but  bears  an  important  relation  to  color  pattern  only  in  some  cases. 

Figures  2  to  33,  plates  I  to  III  are  selected  to  show  the  relation  of 
unpigmented  ai-eas  to  the  main  traclieal  trunks.  Figure  2  shows  four 
cross  bands  which  are  cut  across  by  the  tracheae.  Figures  3  and  4  show 
the  same  type  of  pattern  but  with  the  cross  bands  narrower,  the  middle 
one  broken  in  the  region  of  the  trachea  toward  the  right  and  with  a  sug- 
gestion of  two  or  three  stripes.    Figure  5  shows  a  similar  condition  but 


16  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [410 

with  the  sjjots  in  the  upi^er  right-hand  third  of  the  elytron  missing. 
Figure  6  sliows  a  suggestion  of  seven  cross  bands  as  numbered.  Figures 
8  and  9  are  similar  but  somewhat  broken  and  with  some  tendency  to 
forming  longitudinal  stripes  between  the  tracheae.  Figure  9,  Plate  I 
shows  a  longitudinal  row  of  spots  and  figures  10  to  13,  Plate  II  either 
rows  of  spots  or  continuous  longitudinal  bauds  between  the  tracheae. 
Figures  14  to  21,  Plate  III  show  forms  that  have  lost  most  of  their  pig- 
ment and  have  retained  it  only  in  the  lines  of  the  tracheae.  Figure  18 
shows  a  form  that  appears  to  have  double  longitudinal  lines  between  the 
tracheae  and  has  lost  the  unpigmented  areas  in  the  anterior  part  of  the 
elytron.  Figures  16,  20,  and  21  show  forms  that  ai'e  highly  specialized 
as  to  the  patterns  and  have  lost  most  of  the  pigment  and  the  media 
trachea  is  almost  gone.  It  will  be  noted  that  there  are  many  interesting 
curves  and  branches  that  are  related  to  the  color  pattern. 

Figures  23  to  25,  plate  III^sliow  an  oblique  joining  of  the  markings 
to  form  a  vitta  that  is  not  related  to  the  trachea  and  is  rather  rare,  con- 
stituting an  exception  to  the  usual  rule. 

As  a  result  of  this  study  of  the  figi;res  it  is  seen  that  in  the  color 
patterns  of  the  genus  Cicindela  exists  a  system  of  markings  that  is  related 
to  the  tracheae,  and  also  is  arranged  with  reference  to  the  cross  bands 
of  which  there  are  five,  two  of  which  may  be,  divided  as  to  make  seven 
and  that  these  are  arranged  as  follows:  Therei  is  a  cross  baud  in  the 
center  of  the  longest  measurement  of  the  elytron.  This  location  is 
shown  to  be  the  same  in  essentially  all  of  the  cases  by  actual  measure- 
ment. There  is  one  at  the  tip  and  one  at  the  base,  with  one  or  two 
arranged  respectively  between  each  of  the  latter  and  the  middle  one. 
These  intermediate  bands  are  most  commonly  represented  as  one  but 
are  some  times  divided,  but  in  any  case  its  center,  or  the  center  of  the 
intervening  pigmented  area  is  half-way  between  the  two  adjacent,  un- 
pigmented more  permanent  cross  bands.  It  is  also  evident  that  there 
is  a  possibility  of  fusion  of  joining  of  light  areas,  so  that  these  lines  of 
fusion  are  in  the  spaces  between  the  tracheae  and  in  the  region  of  the 
cro.ss  bands. 

The  areas  near  the  hairs  described  in  a  preceding  section  are  the 
very  last  to  lose  their  pigment  in  the  forms  that  become  almost  entirely 
without  pigment.  It  is  to  be  noted  that  in  the  forms  that  have  the 
longitudinal  stripes  and  cro.ss  bands  broken  up,  the  media  is  almost 
entirel.y  gone.  It  has  been  shown  that  these  cross  bands  are  the  most 
constant  wing  markings  in  insects  and  are  usuall.y  represented  as  the 
i},ve  first  mentioned.  I  have  gone  over  very  large  series  of  Coleoptera, 
(Tower,  1906),  and  find  that  tliis  is  true  for  tliis  order,  while  cross 
bands  in  the  Lepidoptera  (Braun,  et  al.  cited),  Diptera.  Ortlioptera, 
Tricoptera,  Pleeoptera,  Heraiptera,  have  been  discussed  by  Von  Linden, 


411]  COLORS  OF  TIGER  BEETLES—SHELFORD  17 

Eimer,  et  al.  In  the  Lepidoptera  (Mayer),  however,  the  line  of  the 
veins  is  the  one  in  which  pigment  is  longest  absent,  but  in  the  Diptera 
both  living  and  fossil  there  is  a  uniformly  denser  pigmentation  of  the 
veins.  Doctor  Williston  teUs  me  that  it  is  true  of  the  fossil  forms,  and 
Doctor  C.  F.  Adams  found  in  the  development  of  the  color  pattern  of 
some  common  ilies  that  pigment  first  appeared  along  the  cross  veins 
and  spread  from  these.  In  the  Hymenoptera  the  veins  are  often 
pigmented  and  the  same  is  true  of,  the  Mecoptera,  Plecoptera,  some 
Ilomoptera,  etc.  Pigment  is  usually  found  in  muscle  attachments  and 
wherever  rigidity  is  necessary;  this  has  been  reported  by  Tower  (1906) 
in  Coleoptera,  and  in  Polistes  by  Entemau  (1905).  Since  the  veins 
are  supporting  structures,  one  Moidd  expect  that  they  would  usually  be 
pigmented.  The  great  development  of  the  secondary  cuticula  in  the 
Coleoptera  might  since  the  el.ytra  are  no  longer  used  as  wings,  .show 
modification  characterized  by  the  loss  of  this  character  in  some  eases.  I 
find  no  observations  on  the  secondary  cuticula  of  the  wings  of  Lepi- 
doptera. 

In  the  Ctenostomidae  are  found  bands  in  some  of  all  of  these 
positions  noted  in  Cicindela  (Figs.  26  and  27,  PL  III,  also  376,  PL 
XYI.) 

In  the  Collyridae  it  appears  that  the  band  at  the  base  of  the  elytron 
{!),  one  in  the  middle  (4),  and  the  one  at  the  tip  (7),  are  quite  common 
and  well  developed  (one  or  all).  Collyris  celebensis  Chd.  (Fig.  28) 
and  arnoldi  McL.,  horsfieldi  McL.,  fasciata  Chd.  et  al.  have  such  bands. 
In  Theratidae  are  found  markings  which  conform  to  the  cross  bands  of 
Cicindela,  (Figs.  332  to  337,  PL  XVI),  but  the  areas  represented  in 
the  two  ends  of  the  elvtron  niav  be  much  extended  (Figs.  236  and  237, 
PI.  XIII). 

Turning  to  the  other  form  of  the  Cicindelidae  proper,  one  finds 
that  in  the  Euryodini  and  the  Odontochilini  markings  occur  in  the  same 
relations  to  structures  as  those  already  described.  Among  the  Euryodini, 
in  Caledonica  occur  some  of  these  cross  bands  indicated,  and  in  addition 
a  very  interesting  thickening  of  the  elytron  in  the  lines  of  tlie  tracheae 
(Shelford  1915:  Fig.  25).  These  may  or  may  not  correspond  to  the 
thickenings  that  are  associated  with  the  veins  of  other  insects,  for  iu 
the  Dromicini.  (Cicindelidae  proper)  we  find  thickenings  that  lie  be- 
tween the  veins  and  may  be  regularly  arranged  (1.  c.  Figs.  35 
and  36).  It  will  be  noted  that  there  are  spots  in  places  corresponding 
to  those  already  mentioned. for  example,  crossbands  in  figure  29  repre- 
senting the  Odontochilini,  and  longitudinal  stripes  in  figure  30  repre- 
senting the  Dromicini. 

In  the  Megacephalidae  the  color  patterns  are  in  some  cases  like  that 


18  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [412 

shown  ill  figures  370-372,  plate  XVI,  which  accord  with  those  of  Cicin- 
tlela.  Ill  Megacephala  klugi  we  find  a  curious  dark  spot  in  the  position 
of  the  cross  veins  between  the  subcosta  and  the  ramus  which  corres- 
ponds to  the  condition  that  Tower  (1906)  has  called  attention  to  in  the 
Coleoptera,  Lepidoptera,  etc.,  but  it  is  not  of  frequent  enough  occur- 
rence to  be  significant.  I  know  of  no  color  patterns  in  the  Palaeomau- 
tichoridae  or  the  Neomantichoridae/  both  the  wings  are  rudimentary 
and  in  the  latter  the  eyes  are  much  'reduced  and  they  are  in  some  eases 
light  avoiding. 

In  Platychila  pallida  we  have  only  a  very  slight  pigmentation  any- 
where on  the  body ;  the  wings  are  reduced  to  a  rudiment  that  is  barely 
distinguishable  and  the  elytron  is  pigmented  only  in  a  small  area  lying 
in  its  anterior  two  thirds  and  along  its  inner  side.  There  is  no  develop- 
ment of  spaces  in  the  secondary  cuticula  sufficient  to  make  the  chitin 
opaque  and  yellow. 

In  the  Dytiscidae,  Carabidae,  and  Haliplidae,  the  chitinous  columns 
are  arranged  in  definite  rows  and  likewise  in  many  cases  the  hairs  and 
glands.  The  center  of  these  chitinous  columns,  or  better  the  primary 
cuticula  over  the  chitinous  columns,  is  last  to  lose  its  pigment;  accord- 
ingly one  may  find  a  line  of  pigmented  spots  lying  in  rows,  often  two 
rows,  between  the  tracheae,  for  example  as  is  shown  in  the  Bembidium 
versicolor  Lee.  (Pig.  35).  The  row  of  chitinous  columns  break  across 
the  white  markings  and  in  some  of  our  common  Haliplidae,  for  example, 
the  chitinous  columns  are  so  arranged  and  the  centers  are  associated 
with  the  openings  of  glands,  the  cells  of  which  have  caused  the  column 
to  be  cut  half  in  two. 

To  find  what  are  the  conditions  of  the  tracheal  structures  in  other 
Adephaga  I  made  an  examination  of  a  number  of  forms  in  the  Dytis- 
cidae, Carabidae,  and  Haliplidae,  (Figs.  34  to  41,  PI.  IV).  Omophron 
shows  all  six  tracheae  and  three  cross  bands  which  do  not  appear  to  be 
related  to  the  tracheae.  Bembidium  versicolor  shows  only  five  tracheae, 
but  the  unpigmented  areas  are  in  the  lines  of  the  tracheae  and  also 
between  them.  Nebria  complanata  (Fig.  37,  Europe)  shows  the  tra- 
cheae in  the  lines  of  pigmentation  as  well  as  a  suggestion  of  the  double 
banding  shown  in  the  Dytiscidae.  The  Dytiscid  {Hydacticus  stagnalis. 
Fig.  38)  shows  all  of  the  six  tracheae  and  a  light  line  both  between  and 
directly  above  them.  Figure  39  (Laccophilus  rnaculosus)  shows  suggest- 
ions of  cross  bands  and  double  stripes.  Agabus  temiolatus  (Fig.  40) 
shows  the  tracheae  within  the  lines  of  the  unpigmented  cuticula.  Hydro- 
porus  undulatus  (Fig.  39)  has  the  cross  bands  and  the  tracheae  appar- 
ently between  the  spots.    (Compare  with  figures  2  to  25,  plates  I  to  III). 

From  the  studies  preceding,  especially  the  last,  it  is  observed  that 
there  is  no  constant  relation  between  the  tracheae  and  the  distribution 


413]  COLORS  OF  TIGER  BEETLES— SHELFORD  19 

of  the  majiings  or  iinpigmented  areas,  of  such  a  character  as  to  suggest 
a  direct  pliysiologieal  relation  between  the  two.  In  the  specimens  in 
which  the  tracheae  are  unusually  arranged  there  is  no  effect  on  the  color 
pattern  or  variation  on  that  suggests  a  direct  relation  between  the  two. 
Nor  is  there  any  connection  between  the  oxygen  supply  from  the 
tracheae  and  the  pigment.  And  as  the  blood  sinuses  and  tracheae  are 
for  the  most  part  coincident,  I  see  no  reason  for  relating  the  blood 
supply  to  these  characters.  The  folding  of  the  elytron  in  the  pupa  is 
apparently  not  related  to  the  cross  bands.  It  accordingly  appears  that 
the  relation  of  pigment  formation  in  the  elytron  to  structure  is  not 
directly  causal,  at  the  present  stage  in  the  evolution  of  the  groups  but 
is  one  belonging  to  the  general  structural  organization,  hereditary  in 
character. 

THE    COLOR   PATTERN   PLAN 

The  pattern  of  the  Cicindelae  is  analyzable  into  the  areas  or  tend- 
encies sho^^Ti  in  figures  42  to  49,  plate  V.  Figure  42  shows  the  full 
number  of  dark  and  light  longitudinal  stripes.  The  light  stripes  are 
labeled  a,A,B.C ;  a  is  not  usually  distinct.  Very  often  it  is  absent  as  in 
figures  3,  4,  6,  and  11,  but  sometimes  appears  to  be  present  without  A 
as  in  figures  5  and  13,  plate  I  and  II.  It  is  often  present  and  partially 
separated  from  A  in  an  Australian  species  (Pigs.  50  and  51,  PI.  VI) 
only.  This  Australian  species  is  the  basis  for  figure  42.  More  often  it 
is  joined  with  A  (Fig.  43),  and  not  recognized  separately  (Fig.  52). 
Figure  44  indicates  a  tendency  to  double  lines  between  the  tracheae 
suggested  by  an  African  species  (Fig.  53,  also  57  and  7  and  8).  Figures 
54  and  56  show  the  longitudinal  stripes  partially  represented. 

Figue  45  shows  the  full  niunber  of  cross  bands  rarely  complete 
numbered  1  to  7 ;  but  perhaps  best  represented  in  figures  57  and  59  to 
63  where  they  occur  broken  two  spots.  Bands  5  and  6  occur  nearly 
complete  oftener  than  2  and  3  (Figs.  57  and  75).  Figure  46  shows  the 
type  in  which  2  and  3,  and  5  and  6  are  fused.  This  is  almost  a  duplicate 
of  the  pattern  of  an  .\frieau  species,  figure  58,  but  also  well  represented 
bj-  figures  73  and  74.  Figure  47  shows  a  common  type,  cross  bauds 
5  and  6  being  separate  but  the  more  anterior  ones  being  reduced  at  the 
anal  side  of  the  elytron.  Figure  48  shows  all  the  possible  spots  which 
resulted  from  the  superposition  of  the  longitudinal  stripes  and  cross 
bauds.  There  are  19  of  these,  of  which  11  occur  in  an  Indian  species 
(Fig.  62). 

Figure  49  shows  the  spots  or  elements  from  which  the  characteristic 
patterns  of  the  group  are  made  up.  This  pattern  should  be  compared 
with  figures  31  to  33,  plate  III.  which  show  that  individual  variations 
follow  the  rule  of  the  entire  group.     The  usual  pattern  of  C.  tranque- 


20  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [414 

Varica  Herbst  is  seen  to  be  made  up  of  Al,  A2,  B3  {humeral  luniilc)  ; 
A4,  B4,  B5,  Co  {middle  hand)  ;  and  A6  and  7  {apical  lunule).  In  figure 
31  may  be  noted  the  forward  hook-like  extension  on  the  so-called 
humeral  lunule  which  represents  B2,  the  union  between  B5  and  C6,  etc. 

Figures  61  to  72,  plate  VI  indicate  some  of  the  commoner  combin- 
ations of  spots.  Figure  66  shows  a  union  between  the  humeral  lunule 
and  A3 ;  figure  70  a  combination  of  7,  with  B6  and  B5  which  are  connect- 
ed with  the  central  cross  band ;  figure  71  a  cross  connection  in  baud  2-3 
between  stripes  A  and  B ;  figure  72  a  cross  connection  in  band  4  between 
A  and  B ;  figures  76  to  77,  plate  VI  show  the  reduction  of  cross  bands 
to  large  spots.  Thus  the  conclusion  that  the  patterns  are  derivable  from 
combination,  loss,  and  extension  of  a  number  of  inter-tracheal  spots  fall- 
ing in  cross  rows  seems  justified.  There  are  various  types  of  combina- 
tion and  extension  which  are  not  common  when  the  group  is  considered 
as  a  whole,  but  which  represent  tendencies  in  certain  isolated  groujjs  of 
species  and  which  must  be  illustrated  (Figs.  78  to  98,  PI.  VII)  here 
because  they  othewise  appear  to  be  obstacles  to  the  plan.  One  of  these 
tendencies  is  one  toward  oblique  combinations  indicated  in'  figure  78 
(a  diagram).  One  type  indicated  by  the  wide  stippled  band  is  shown 
in  figure  79,  a  South  American  species.  A  similar  combination  occurs 
as  a  variation  in  an  Indian  species  (Fig.  80).  A  more  gentle  sweeping 
combination  is  shoA\Ti  by  the  narrow  white  line  in  figure  78  and  occurs 
as  the  regular  pattern  of  an  African  species  (Fig.  81)  ;  shorter  curves 
occur  in  another  African  species  (Fig.  82).  Other  oblique  combinations 
are  shown  in  figiires  83  and  84.  The  type  of  obliqueness  shown  by  sev- 
eral African  species  (Figs.  85  to  87)  is  an  oblique  shifting  of  the  entire 
pattern ;  it  appears  to  be  turned  parallel  to  the  end  of  the  elytron.  This 
appears  to  be  a  significant  tendency  and  will  be  discussed  again  in  con- 
nection with  the  discussion  of  experimental  results. 

Figures  88  to  91  show  a  tendency  toward  obliqueness  of  markings 
reversed  as  compared  with  that  just  described  and  characteristic  of  the 
princeps-cylanensis  gi-oup  of  India  and  Africa.  It  may  be  said  to  char- 
acterize the  patterns  of  a  group  standing  apart  from  the  other  represen- 
tative of  the  genus. 

Figures  92  to  95,  plate  VII  show  unusual  sinuate  extensions  of  the 
markings.  In  figures  92  and  93,  Indian  and  Australian  species,  a  mark- 
ing resembling  the  usual  "middle  band"  arises  in  the  area  A2.3  with  a 
form  similar  to  that  found  in  figiires  94  and  95.  Figure  96  shows  bands 
5  and  6  separate  toward  the  outer  margin  of  the  elytron  and  united 
toward  the  inner.  Figure  97  shows  unusual  extensions  of  the  markings 
giving  two  light  bands  between  the  tracheae  (compare  with  Fig.  19,  PI. 
II)  ;  98  shows  unusual  direction  of  extension. 

From  the  preceding  discussion  and  diagrams  I  concluded  that  even 


415]  COLORS  OF  TIGER  BEETLES—SHELFORD  21 

the  most  complicated  patterns  are  redncable  to  the  usual  plan  or  are 
made  up  of  unusual  combinations  of  spots  occurring  in  other  groups  of 
species.  Certain  laws  regarding  direction  of  shifting  of  markings  seem 
to  prevail.  These  will  be  noted  again  in  another  part  of  the  paper, 
(page  58). 

COLOR  PATTERN  AXD  PIGMENT  DEVELOPMENT 

As  an  example  of  the  usual  type  of  pigment  development  in  Cicin- 
dela  let  us  follow  the  events  in  C.  tranqueharica  (PI.  VIII).  In  the 
yoiingest  pupae  there  is  essentially  no  pigment  present  except  sufficient 
in  the  eyes  to  give  a  slight  brown  color.  This  gradually  becomes  darker 
until  tlie  end  of  about  ten  days  when  the  eyes  are  a  dull  brown  and  the 
process  is  apparently  complete.  At  the  end  of  12  days  the  tarsal  claws, 
the  tip  of  the  mandibles,  and  the  tips  of  the  mandibular  teeth  have 
received  their  full  quota  of  pigment ;  the  pigment  proceeds  from  the 
tips  proximally  and  by  the  13th  and  14th  day  pigmentation  is  com- 
plete. On  about  the  13tli  day  the  distal  portion  of  the  tibia  of  all  of  the 
legs  show  pigmentation  on  the  outer  side  and  this  proceeds  to  the  more 
pi'oximal  portions  most  rapidly  on  the  outside  of  the  leg.  The  most 
distal  parts  of  the  tibia  are  pigmented  about  2  or  3  days  later.  Coin- 
cident with  the  development  in  the  tibia  is  the  development  in  the 
trochanters  where  it  begins  at  the  outer  margin.  A  slight  darkening 
takes  place  in  the  mid-portion  of  the  developing  hind  wing  which  is  so 
folded  as  to  make  the  tip  of  the  pupal  wing  show  dark.  At  this  time, 
viz.,  at  the  end  of  from  14  to  16  days,  the  insect  emerges.  Often  at  or 
before  the  time  of  emerging  the  first  color  centres  of  the  dorsal  side 
of  the  abdomen  have  appeared  on  the  last  abdominal  segment  and  more 
rarely  also  the  corresponding  centers  of  the  next  to  the  last  segment 
are  also  present  (Fig.  105,  PI.  VIII).  Usually  the  animal  en:erges 
with  the  tibia,  tarsal  claws,  part  of  the  trochanters,  eyes,  mid-portion 
of  the  hind  wing,  and  tips  of  the  mandibles  pigmented  (Figs.  101  and 
105a). 

The  later  histon-  exclusive  of  the  elytra  is  as  follows:  Tlie  pig- 
mentation begins  first  on  the  distal  joint  of  the  antennae  and  the  max- 
illary palps  (Fig.  101),  and  on  the  teeth  of  the  maxillae.  After  about 
8  hours  the  tip  of  the  inner  palp  and  the  ligular  portion  of  the  labium 
shows  pigment  (Fig.  102)  ;  next  after  about  12  liours  the  distal  segment 
of  the  labial  palp  and  the  outer  wings  of  the  labium  darken  (Fig.  103). 
The  gula  begins  to  show  pigment  about  as  soon  as  the  ligula,  and  the 
pigmentation  of  this  part  is  complete  at  the  end  of  12  to  15  hours.  At 
tlie  time  (after  12  to  15  hours.  Figs.  103  and  107)  the  general  pigmenta- 
tioji  begins  to  be  most  rapid,  pigmentation  begins  to  show  strikingly 
at  the  proximal  portion  of  the  appendages  just  noted  and  proceeds  to 


22  ILUXOIS  BIOLOGICAL  MONOGRAPHS  [416 

meet  the  distal  pigmentation  (Zeleny,  1907).  The  extent  to  which  it 
goes  differs  in  different  species  and  gives  a  faint  pattern  to  the  parts  in 
some  species.  The  pigmentation  which  begins  distally,  usually  pro- 
ceeds only  through  the  extent  of  the  more  distal  segments  (Fig. 
109  a  to  e).  By  the  end  of  24  to  36  hours  (Fig.  104)  the  pigmentation  is 
nearly  complete  by  development  over  the  general  areas  of  both  body 
and  appendages.  Thus  in  the  antenna  at  the  end  of  8  to  10  hours  rings 
appear  toward  the  distal  end  of  the  tliree  proximal  segments,  darken 
and  spread  toward  the  proximal  ends  of  the  segments  rapidly  (compare 
Pigs.  109  c,  d,  and  e).  The  pattern  shown  in  the  antennae,  legs, 
mandibles,  palps,  etc.,  persist  in  some  species  (see  page  24). 

At  3  to  6  hours  after  emergence  (Fig.  105a)  the  suture  between  the 
clipeus  and  head  becomes  pigmented.  By  the  end  of  8  hours  after 
emergence  there  are  two  oblique  color  centers  between  the  centers  of 
the  eyes;  these  correspond  in  position  to  the  oblique  depressions 
that  occur  in  the  genus  Tetracha.  Beside  these  there  is  a  center  close 
to  the  posterior  side  of  each  eye,  one  just  behind  and  inside  of  this, 
and  one  in  the  middle  of  the  frons  (Fig.  106).  Pigmentation  then  has 
proceeded  backward  on  the  clipeus,  and  backward  from  the  suture  of 
the  cUpeus  on  the  head  (Fig.  106).  At  the  end  of  12  to  15  hours,  the 
pigment  of  the  clypeus  and  anterior  part  of  the  frons  and  centers  just 
described  has  increased  and  extended  backward,  giving  a  pattern  as 
shown  in  figure  107.  This  process  continues  with  general  suffusion 
over  the  head  with  the  pattern  still  in  evidence  at  the  end  of  24  to  36 
hours  (Fig.  108). 

After  8  to  10  hours  after  emergence  (Fig.  106)  the  posterior  border 
of  the  thorax  shows  two  centers  in  the  depression  at  the  posterior  side. 
Little  change  takes  place  on  the  under  side  from  emergence.  By  the 
end  of  12  to  15  hours  (Fig.  107)  the  thorax  has  presented  some  new 
centers,  a  longitudinal  stripe  occurs  near  each  margin,  and  there  is  a 
narrower  one  between  each  of  these  and  the  center,  and  the  anterior 
depression  is  darker  than  usual.  The  end  of  24  to  36  hours  (Fig.  108) 
shows  the  obliteration  of  the  centers  mentioned  above  by  tlie  pigmenta- 
tion of  the  inter-spaces. 

On  the  ventral  side  of  the  abdomen  and  thorax  pigment  begins 
on  the  outer  side  of  the  more  posterior  segments  first  and  centers  appear 
from  behind  forward.  During  the  first  few  hours  the  pigmentation 
does  not  begin  on  the  remainder  of  the  abdomen.  The  next  center  to 
appear  is  the  one  in  the  center  of  each  segment  near  its  anterior  side, 
which  appears  between  the  6th  and  10th  hour.  Just  a  little  later  a  line 
appears  across  the  posterior  side  of  the  segment  and  there  is  an  exten- 
sion of  the  center  one  at  each  side  and  the  coming  in  of  the  a  loop-like 
addition  outside  of  the  first  center.     This  svstem  of  markings  is  best 


417]  COLORS  OF  TIGER  BEETLES— SHELFORD  23 

understood  b.y  a  eomparisou  with  the  larval  segments  (Fig.  99  a,  h,  and 
aa).  If  a  and  b  joined  to  give  the  first  marking  that  appears,  «a  stand- 
ing out  clearly  and  all  of  the  rest  joined  laterally,  one  would  have  the 
condition  found  in  the  development  of  the  adult  color. 

No  change  takes  place  in  the  thorax  except  the  development  of  a 
center  of.  tbo  on  the  middle  line  of  the  meta-sterniim  which  probably 
repi-esents  the  attachment  of  the  large  hind  wing  muscles  (Fig.  102), 
until  the  coloration  of  the  abdomen  is  has  been  completed  in  the  veuti'al 
side  of  the  third,  fourth,  and  fifth,  and  last  abdominal  segments;  this  j 

having  proceeded  from  behind  forward.     At  the  end,  12  to  15  hours       0' i 
(Fig.  103),  it  will  be  noted  that  the  hind  coxae,  the  ante-eoxal  pieces,  ] 

the  epistema  of  the  metathorax  and  the  coxae  of  the  other  segments 
have  received  a  quantity  of  pigment  and  a  new;  center  has  developed 
behind  each  metathoracic  leg  on  the  metathoracic  sternum.  The  next 
stage  represented  (24  to  36  hours,  Fig.  104)  shows  a  general  diffuse 
pigment  on  the  entire  ventral  surface  except  the  outer  sides  of  the 
metathoracic  coxae  which  long  remain  unpigmented.  The  ante-coxal 
piece  is  nearest  complete.  The  great  possibilities  of  being  deceived  as 
to  position  of  the  color  centers  is  shown  by  the  fact  that  the  abdominal 
centers  and  center  behind  the  legs  on  the  metathoracic  segments  is  lost 
entirely  in  the  last  stage  of  the  development. 

Conditions  on  the  dorsal  side  are  very  simple  and  centers  appear 
just  as  in  the  larvae  (Fig.  100)  two  in  number  on  each  segment,  begin 
on  the  last  segment,  and  move  forward  fusing  in  the  middle  line,  and  in 
course  of  about  10  hours  after  emergence  (Figs.  106  and  107)  the  color 
of  the  dorsal  side  of  the  abdomen  is  practically  complete. 

In  regard  to  the  color  centers  of  the  ventral  side  of  the  abdomen 
it  may  be  said  that  they  are  the  same  in  number  and  arrangement  as 
found  by  Tower  on  the  ventral  side  of  the  abdomen  of  the  potato  beetle 
larvae.     The  abdominal  centers  are  serially  homologous.     The  pattern  , 

of  the  dorsal  side  of  the  abdomen  of  the  larvae  if  Leptinotarsa  is  similar  ^/ 
to  that  of  the  ontogenetic  ventral  of  the  adult  C'icindela.  The  upper  side 
of  the  abdomen  in  the  potato  beetle  larvae  is  divided  with  respect  to 
these  structures  because  growth,  bulging,  and  wrinlding  due  to  the 
extension  divide  the  dorsal  side  into  two  parts,  and  have  resulted  in  the 
separation  of  the  centers  into  two  rows  or  bands  (see  Tower.  1906: 
PI.  18).  In  the  larval  Cicindelidae,  however,  it  is  the  ventral  side  that 
is  extended  in  the  process  of  the  development  and  which  may  be  wrinkled 
and  the  centers  are  separated  just  as  in  the  case  of  the  dorsal  side  of  the 
abdomen  in  the  larvae  of  Leptinotarsa.  There  is  never  any  tendency  for 
the  dorsal  side  of  the  cicindelid  abdomen  to  wrinkle ;  in  fact  it  is  reduced 
as  compared  with  ventral.  On  the  ventral  side  of  the  adidt  Leptinotarsa 
abdomen  six  centers  appear  but  these  are  not  divided  as  to  the  middle 


hi 


24  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [418 

of  the  segment.  Tower's  basipleural  is  no  doubt  represented  by  the 
three  spots  that  are  near  the  spiracle  (Fig.  99,  PL  VII). 

In  the  prothorax  of  the  tiger  beetles  it  is  to  be  noted  that  the  onto- 
genetic coloration  is  parallel  to  that  in  some  of  the  Leptinotarsae ;  the 
two  pairs  of  parallel  lines  which  occur  appear  to  eorresiDond  to  markings 
that  are  on  the  prothorax  of  the  C.  tranqucharica  (Fig.  107).  The  two 
oblique  centers  of  the  frons  or  epicranium  in  the  Cicindelidae  are  rep- 
resented in  the  Leptinotarsae  also  the  two  markings  by  the  eyes. 

I  have  noted  that  in  the  aiitennae  centers  arise  in  the  form  of  rings 
around  the  distal  ends  of  the  2d,  3d,  and  4th  segments  (Fig.  109  c,  d,  e.). 
Conditions  in  figure  109d  and  c  show  patterns  in  the  tlevelopment  of 
these  which  are  the  exact  duplicate  of  the  patterns  in  the  antennae  of 
the  G.  strachani  (Africa)  which  has  also  a  primitive  elytral  pattern.' 
C.  theratoides  (New  Guinea),  many  of  the  Megacephalidae  and  some 
Collyridae. 

The  development  of  the  pigment  in  the  legs  up  to  tlie  time  of 
cmergencq  is  described  above ;  after  emergence  the  development  pro- 
ceeds from  proximal  to  distal  in  the  tibia  and  in  the  same  succession 
in  the  tarsal  segments.  Previous  to  emergence  the  humerus  is  somewhat 
compressed  and  wrinkled,  being  only  about  two-thirds  as  long  as  after 
the  expansion  which  follows  emergence.  At  the  end  of  about  8  hours 
one  finds  the  feruAr  beginning  to  show  a  general  suffuse  pigment  which 
appears  to  arise  snnultaneously  over  the  entire  surface.  After  this  the 
later  liistory  in  tlie  legs  im  simply  a  general  intensification  of  the  pig- 
mentation. 

In  all  of  the  species  of  Cieindela  studied  the  phenomena  of  pigment 
development  are  the  same  so  far  as  has  been  noted  above  with  the 
exception  of  the  ptinctulata  and  lepida  in  which  the  first  centers  appear 
in  the  middle  of  the  ventral  side  in  the  third  and  fourth  abdominal 
segments.  This  is  tlie  case  in  T.  Carolina  in  which  the  centers  are  like 
those  in  the  larvae.  The  adult  abdomen  in  this  species  is  not  pigmented 
toward  the  posterior  end  of  the  ventral  side  while  the  upper  side  never 
receives  any  pigment  at  all  and  the  usual  larval  color  center  are,  as  has 
been  stated,  very  much  reduced  in  this  species.  Likewise  the  centers  of 
the  head  and  prothorax  are  little  developed  and  the  obliqiie  ones  near 
the  center  of  the  frons  are  very  faint.  The  two  which  appear  first  in 
the  posterior  depression  of  tlie  prothorax  are  quite  distinct  and  very 
suggestive  of  the  condition  in  the  MegcicrpJuda  (Phacoxantha)  khigi. 
The  legs  are,  however,  not  pigmented  at  all  and  it  appears  that  the 
cuticula  in  these  cases  is  of  the  type  with  interlamellar  spaces  which  is 
a  means  of  giving  strength  to  the  less  rigid  parts  of  the  body. 

An  examination  of  stained  whole  mounts  of  the  appendages  shows 
that  as  a  rule  the  distal  portions  are  first  clearly  differentiated  and 


419]  COLORS  OF  TIGER  BEETLES—SHELF ORD  25 

iirst  to  take  on  the  form  that  the  part  is  to  have  in  the  adult.  The  tip 
of  the  mandible  is  the  first  to  sliow  the  distinct  pointed  form  toward 
the  head,  tooth  after  tooth  being  differentiated  from  the  somewhat  larger 
mass  of  tissue  which  makes  iip  the  mandibular  outgrowth.  The  same  is 
true  of  the  other  mouth  appendages,  labrum  etc.,  the.y  become  more 
hairj-  in  form  and  stand  well  separated  from  the  old  pupal  skin.  In  the 
ease  of  the  leg  the  tarsal  claws  are  the  first  differentiated  and  this  pro- 
cess appears  to  move  in  a  general  way  toward  the  body,  segment  by 
segment,  the  femir  being  last  to  be  differentiated  and  last  to  receive  the  (/^  / 
pigment.  The  position  of  the  pigmentation  in  the  tibia  corresponds  to 
the  point  of  attachment  of  the  flexor  of  the  tarsi.  This  is  early  developed 
and  thus  the  tarsi  are  the  first  to  become  movable ;  at  this  time  the 
flexor  and  extensor  of  the  tibia  are  not  well  developed,  their  muscle 
striations  appearing  indistinct,  but  become  much  more  distinct  and 
definite  in  form  a  little  later  and  the  tibia  becomes  movable  about  the 
time  of  this  development  of  its  pigmeut.  A  similar  development  occurs  V 
on  the  proximal  portions  of  the  trochanters  which  are  the  attachment  of  . 

the  muscles.  The  wrinkled  condition  of  the  femosa  helps  to  give  it  t^-V/ 
rigidity  and.  the  legs  are  well  enough  developed  to  allow  of  sufficient 
movement  to  release  the  animal  from  the  pupal  skin.  The  legs  are  at 
first  somewhat  extended  and  subject  to  a  considerable  amount  of  move- 
ment, and  while  the  body  is  flexed  and  extended  and  the  pupal  skin 
ruptured  in  the  midline  of  the  thorax  the  mandibles  are  then  worked 
as  well  as  the  other  mouth  parts  and  the  head  removed  by  repeatedly 
throwing  it  backward.  The  animal  gradually  wriggles  out  of  its  skin 
and  the  wings  and  elytra  soon  expand ;  the  wings  expand  to  the  full 
length  inside  of  about  20  minutes  after  the  animal  emerges,  and  remain 
thus  for  several  hours.  If  for  any  reason  the  expansion  of  the  wings 
or  elytra  is  interferred  with,  they  always  remain  in  the  exact  condition 
in  which  they  were  placed  by  the  adverse  conditions,  and  if  the  wings 
are  not  folded  in  the  normal  fashion  at  the  proper  time,  they  will 
always  remain  completely  extended.  Their  early  pigmentation,  if  it  is 
associated  with  hardening,  is  probably  an  advantage  to  this  process  of 
withdrawal  or  folding. 

It  seems  altogether  probable  that  the  peculiar  manner  of  develop- 
ment of  the  pigment  is  associated  with  the  development  of  the  structures 
which  are  necessarv'  to  ectosis  and  that  they  accordingh-  represent  de- 
velopmental adaptations.  In  the  ease  of  the  tiger  beetles  which  do  not 
have  the  appendages  pigmented  in  the  adult  the  cuticvila  must  harden 
without  being  pigmented. 

The  animals  emerge  M'ith  the  elytra  entirely  unpigmented  and  dur- 
ing the  first  4  to  8  hours  little  change  is  easily  noted.  One  can  hardly 
record  the  beginnings  of  the  pigmentation  as  this  is  verj'  faint,  and  the 


26  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [420 

wings  beneath,  which  come  between  the  elytron  and  a  part  of  the  pig- 
mented abdomen,  give  no  opportunitj'  for  accurate  observations  with 
the  elytra  in  position  except  as  one  slips  pieces  of  paper  under  them, 
which  may  injure  the  elytra  so  as  to  give  abnormal  development.  The 
elytra  must  be  removed  and  mounted  in  glycerine  jelly,  or  cleared  in 
balsam.  It  is  necessary  to  hold  the  slide  in  position  over  the  surface 
of  a  good  glass  plate  that  has  been  painted  white  on  the  lower  surface 
and  uot  magnify  them  or  if  so,  only  about  two  diameters  with  a  reading 
glass.  The  fresh,  unmounted  elytra  may  be  placed  in  formalin  in  a 
watch  glass  painted  a  neutral  gray  or  yellowish  tone  which  is  the  same 
color  as  that  presented  by  the  elytron  before  pigmentation  when  viewed 
in  transmitted  light.  By  this  method  and  with  individuals  killed  at 
different  stages,  and  with  the  use  of  a  Zeiss  binocular  microscope,  I 
have  been  able  to  follow  the  course  of  pigmentation  of  the  elytra.  The 
elytra  have  been  examined  in  cross  section ;  there  are  no  thickenings  in 
the  primary  cutieula  in  which  all  the  pigment  is  located,  except  the 
small  thickenings  that  have  been  described  as  occurring  in  the  area 
immediately  in  front  of  hairs,  and  these  have  been  carefully  considered 
and  their  relative  number  as  effecting  the  color  effect  practically  elim- 
inated. The  cutieula  is  somewhat  thinner  at  the  tip  of  the  elytron.  The 
actual  hairs  present  are  surrounded  by  an  area  that  is  fully  pigmented, 
but  this  also  has  been  taken  into  account.  Elytra  of  C.  repanda  show 
beginnings  of  pigmentation  which  often  are  strongest  near  the  costal 
border  at  the  end  of  4  to  5  hours  (Fig.  111).  The  chief  of  the  areas 
showing  lack  of  pigment  are  in  the  lines  A  and  B  and  are  particularly 
prominent  near  the  base.  Later  (Figs.  112  and  113)  these  lines  are 
broken  into  spots  which  correspond  to  spots  found  in  certain  Eurasian 
and  African  species  (Figs.  147  to  187,  PI.  XII,  and  241  to  280,  Plate 
XIV).  The  series  of  stages  that  I  have  had  has  been  small  and  not  siaited 
to  the  detailed  comparison  as  some  of  the  following  sjjecies  are,  but  shows 
the  same  thing. 

The  color  development  in  C.  lecontei  Hald.  begins  very  faintly 
ajiparently  at  about  the  posterior  end  of  the  anterior  third  of  the  elytron, 
at  first  the  permanent  markings  are  difficult  to  distinguish,  but  a  little 
later  they  become  distinct  patches.  Two  ontogenetic  markings  between 
the  base  of  the  elytron  and  the  general  arrangement  of  pigment  at  the 
end  of  4  to  5  hours  (Fig.  114)  correspond  verj'  closely  to  conditions 
found  in  repanda.  Longitudinal,  heavily  pigmented  stripes  that  stand 
out  in  some  individuals,  lie  in  the  lines  of  the  tracheae  and  hairs,  and 
become  more  pronounced  as  the  development  continues.  Figure  115, 
12  hours  after  emergence,  shows  none  of  the  spots  characteristic  of  the 
others  shown  but  has  indications  of  a  cross  band  which  never  occurs  in 
lecontei  but  which  is  present  in  rugifrons  and  modesta  of  the  Atlantic 


421]  COLORS  OF  TIGER  BEETLES—SHELFORD  27 

coast.  Figui'es  116,  117,  118  sliow  a  number  of  spots  arranged  in  longi- 
tudinal rows.  A  comparison  of  these  witli  figures  156  to  177  and  244  to 
261  will  make  clear  a  close  correspondence  between  the  spots  appearing 
and  those  in  adults  of  Eurasian  and  African  species.  Pigment  fails  to 
develop  when  tlie  elytron  is  wet  (Gortuer,  1911).  This  happened  in 
practically  all  wet  elytra  of  this  species  and  very  few  of  those  in  other 
species. 

Development  of  pigment  in  the  hind  wings  begins  a  little  back  from 
the  anterior  end,  and  in  this  case,  about  the  time  of  emergence  (Fig. 
119),  in  the  region  in  which  the  folding  occurs,  and  shows  while  the 
wing  is  in  the  pupal  skin  thus  causing  the  tip  of  the  pupal  wing  to  look 
black.  Pigment  passes  out  along  the  veins  in  both  directions  and  vein 
after  vein  is  pigmented  toward  the  anal  border.  This  process  requires 
several  daj's  for  completion.  Figures  119  to  122  show  the  wing  from  the 
time  of  emei'genee  to  the  end  of  about  24  to  36  hours  and  the  adult. 

Development  in  C.  purpurea  Oliv.  var.  limbalis  Klg.  (PI.  X)  per- 
haps shows  more  definite  spots  than  any  of  the  others.  The  first  evidences 
of  the  pigmentation  in  ontogeny  is  in  the  small  circles  around  the  hairs 
on  the  elytron;  this  takes  place  about  3  hours  (Fig.  123)  after  emerg- 
ence. 

At  the  end  of  8  hours  the  pigment  usiially  begins  to  come  in  gen- 
erally, first,  in  the  lines  of  the  tracheae.  As  in  the  case  of  the  lecontei 
the  first  trace  is  at  the  posterior  end  of  the  anterior  third  of  the  ely- 
tron. The  principal  early  developmental  markings  show  as  large  light 
areas  (Figs.  124  and  125,  aftei^  8  to  10  hours)  which  seem  divided 
again  later  (Figs.  126  to  129,  PI.  X)  and  correspond  to  the  spots  found 
in  old  world  species,  figures  of  which  have  already  been  cited.  Heavier 
pigmentation  often  persists  in  tlie  line  of  the  tracheae  even  in  the  adult 
(Fig.  130). 

In  C.  tranqucbarica  (PI.  X)  the  pigment  begins  first  a  little  ])ehind 
the  anterior  end,  as  in  the  other  species,  and  comes  in  the  lines  of  the 
tracheae  with  all  of  the  bands  represented  and  the  spots  growing 
fmaller  and  the  longitudinal  stripes  less  and  less  prominent  as  time  goes 
on.  In  all  tlie  elytra,  liowever,  the  same  markings  appear  as  in  the 
other  species  (Figs.  131  to  134),  and  spots  occurring  in  other  species 
are  consistent  in  occurrence. 

C.  punctulata  (PI.  XI)  begins  pigmentation  about  4  to  6  hours  after 
emergence  and  the  pigment  appears  to  pass  from  the  anterior  to  the 
posterior  end  of  the  elytron.  Certain  lighter  areas  appear  especially  at 
the  base  of  the  elytron  and  between  the  tracheae,  figures  135  to  137. 
These  represent  cross  bands  and  otiier  bands  occur  further  back  appear- 
ing in  some  cases  but  all  are  comparatively  indistinct.  There  is,  how- 
ever, a  different  phenomenon  such  as  occurs  in  some  of  the  Dytiscidae, 


28  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [422 

e.  g.,  LacchopMlus  maculosus  (Fig.  39,  PI.  IV),  a  coucentration  of  the 
pigment  around  the  markings.  Even  where  the  markings  are  absent 
or  ahnost  so  the  denser  pigmentation  is  present.  This  seems  to  have 
obliterated  ontogenetic  markings  as  they  are  shown  less  plainly  in  these 
species  than  any  other  studied.  Such  spots  occur  in  some  species  of 
Cicindela  as  for  example  campestris,  aulica  polysita,  latrcillei  (Fig. 
257,  PI.  XIV)  and  ismenia  (Fig.  366,  PI.  XVI),  which  have  a  more 
densely  pigmented  spot  in  the  region  of  the  sutural  spots  of  other 
species,  i.e.,  in  the  position  of  C2.3  (Fig.  48,  PL  V).  In  cleared  elytra 
of  campestris  a  dark  area  appears  at  this  point.  Elytra  of  C.  limbalid 
(Fig.  127,  PI.  X)  shows  this.  In  some  cases  dark  .spots  appear  at  this 
point  in  surface  view;  in  others  metallic  spots.  When  the  dark  color 
occurs,  the  conditions  described  in  page  51  are  reversed — the  surface 
film  is  absent.  The  distribution  of  the  ehitinous  columns  above  which 
areas  are  first  pigmented  makes  the  study  very  difficult.  The  hairs  on 
the  elytron  which  lie  in  the  lines  of  the  tracheae  show  pigment  around 
their  bases  by  the  end  of  3  or  4  hours  if  not  earlier.  The  elyti-on 
reaches  the  adult  color  so  far  as  pattern  is  concerned  at  the  end  of 
about  15  hours,  but  pigment  continues  to  be  deposited  for  several  days. 

Only  one  stage  of  C.  sexguttata  (Fig.  138)  studied  shows  the  spots 
in  the  area  between  the  tracheae  faintly.  The[  pigment  is  piled  up 
about  the  markings  only  to  a  slight  degree.  C.  punctulata  and  sexgut- 
tata belong  to  one  of  the  Mexican  groups  and  differ  from  the  other 
species  studied. 

One  specimen  of  Tetracka  Carolina  (Fig.  139,  PI.  XI)  was  studied; 
in  this  the  pigment  began  to  develop  at  the  end  of  about  9  hours  and  to 
manifest  itself  at  the  outer  side  of  the  elytron  where  it  bends  under, 
and  appears  to  move  toward  all  parts  of  the  el.ytrou  from  there.  A 
somewhat  lighter  streak  was  left,  however,  between  the  costa  and  the 
subcosta  tracheae;  this  corresponds  to  stripe  a,  figure  139.  The  pig- 
ment moves  toward  the  inner  angle  but  shows  a  lighter  space  at  the 
base  between  the  ramus  and  the  media  and  also  a  longitudinal  stripe 
between  the  media  and  the  cubitus,  which  is  broken  at  a  point  corres- 
ponding with  the  dark  band  B  between  2.3  and  4.  This  same  break 
occurs  in  the  area  between  costa  and  subcosta.  That  portion  of  the  tip 
of  the  elytron  between  the  media  and  the  suture  is  the  last  to  be  pig- 
mented. Figure  140,  which  represents  the  elj'tron  at  the  end  of  9 
hovirs  shows  adult  coloration.  The  darker  dots  represent  the  ehitinous 
columns  over  the  center  of  which  the  primary  pigmented  cutieula  is 
thicker  than  any  where  else.  At  the  point  where  it  has  been  stated  that 
(^  ;  the   pigment  began  developing  the  citicula  is  somewhat  thicker  than 

elsewhere. 


423)  COLORS  OF  TIGER  BEETLES— SHELFORD  29 

In  C.  hirtkoUi^  (Figs.  141  to  145)  the  pigment  appeal's  to  begiu 
almost  uniformly  over  the  elytron  except  for  the  weaker  places  repre- 
senting tlie  ontogenetic  markings.  The  lighter  places  are  between  the 
lines  of  the  tracheae.  There  are  cross  bands  at  the  base  of  the  elytron, 
the  middle  one  usually  moi'e  or  less  clearly  connected  with  the  distal 
end  of  the  adult  cross  band  3.  Usually  there  is  a  spot  opposite  the  end 
of  this  band  between  the  media  and  the  cubitus  and  usually  another 
set  of  dots  stretches  across  the  elytron  between  the  band  2  and  band  4. 
These  bands  of  a  secondarj'  nature  are  not  present  in  the  later  stages  or 
if  so  not  marked.  The  longitudinal  lines  become  weaker  as  time  goes 
on  and  the  markings,  except  those  that  ai'e  to  be  permanent,  gradually 
disappear;  those  in  the  region  of  the  base  are  last  to  go.  In  some  cases 
lighter  longitudinal  lines  are  divided  into  spots. 

A  late  stage  in  C.  12  guttata  shows  the  same  longitudinal  stripes 
and  cross  bands.  Throughout  the  series  longitudinal  stripes  seem  to 
be  most  marked  in  the  earlier  stages  but  become  partially  divided  later 
and  are  rarely  or  never  continuous  but  nearly  always  broken  into  spots. 
This  is  shown  in  nearly  all  the  figures  presented  and  the  conclusion 
which  seems  warranted  is  that  the  longitudinal  stripes  are  a  more  defin- 
ite character  than  the  cross  band,  though  neither  occurs  alone.  The 
fact  of  a  combined  cross  and  longitudinal  system  of  unpigmented  areas 
is  the  one  which  comes  forcefully  forward  in  the  entire  study  though 
there  are  irregularities  present.  Further,  one  sees  a  close  resemblance 
between  the  ontogenetic  patterns  and  those  of  the  African  and  Eurasian 
species  on  which  the  analysis  of  the  pattern  was  based.  One  notes  also 
the  close  correspondence  between  the  spots  sho^vn  in  the  general  plan 
presented  in  figure  48,  plate  V,  and  tliose  occurring  in  the  ontogeny 
of  the  patterns  of  common  North  American  species.  This  would  seem 
to  establish  the  plan  of  the  pattern  as  well  as  could  be  hoped. 

The  entire  set  of  evidence  presented  tends  to  show  that  the  simplest 
type  of  pattern  in  the  Cieindelas  is  a  pattern  of  spots  lying  in  lines  be- 
tween tile  chief  longitudinal  tracheal  trunks  and  falling  into  cross 
bands  of  which  there  may  be  seven.  In  ontogeny  these  are  subject  to 
some  variations  but  such  a  description  fits  the  general  relations  found 
better  than  anything  else  that  can  be  stated.  Such  a  type  of  pattern, 
which  is  of  the  character  that  is  commonly  called  primitive,  is  what 
might  be  expected  among  insects.  The  wings  are  usually  characterized 
by  longitudinal  veins  which  are  thickened  and  hardened  and  often  pig- 
mented. These  veins  are  connected  transversly  by  cross  veins  which  are 
much  more  diversified  in  the  insect  group  than  are  the  longitudinal  ones 
and  which  are  also  much  more  subject  to  individual  variation.  Tracheae 
usually  occupy  tlie  longitudinal  veins  but  not  always  tlie  cross  veins, 
hence  in  the  insects  which  have  actual  cross  veins  there  is  not  a  neces- 


30  ILLISOIS  BIOLOGICAL  MONOGRAPHS  [424 

sary  correlation  between  the  veins  and  the  tracheae.  The  greater  hard- 
ening and  more  general  pigmentation  of  the  veins  of  many  insects 
already  mentioned  (page  16)  leads  to  a  spotted  type  of  wing,  in  many 
cases  at  least.  Such  a  system  oiit'ered  in  the  elytra  of  the  tiger  beetles 
gives  the  basis  for  the  spotted  type  of  elytron  which  we  tiiid  frequently 
in  the  group.  Veins  no  longer  occur  definitely  longitudinally  and  the 
tracheae  do  not  ordinarily  bear  any  definite  relation  to  cross  areas. 

A  large  background  of  evidence  is  presented  above  for  the  selection 
of  the  spotted  type  of  tiger  beetle  pattern,  made  up  of  spots  falling  into 
rows  and  forming  sti'ipes  and  rowS  forming  cross  bauds,  as  a  general 
one  from  which  other  types  are  derivable  iy  the  loss  of  spots,  com- 
iination  of  spots,  etc.  Comparable  analyses  were  presented  by  Eimer 
(1895)  and  Von  Linden  (1902),  Vv'ho  note  cross  bands  as  the  basis  of 
the  patterns  of  various  species  of  Lepidoptera.  Tower  (1906)  reduced 
the  general  plan  of  markings  in  Leptinotarsa  to  cross  bands  and  longi- 
tudinal sti-ipes.  He  recognized  4  or  5  uupigmeuted  cross  bands  and  6 
longitudinal  unpigmented  stripes  which  fall  in  the  lines  with  the 
tracheae  instead  of  between  them  as  in  in  Cicindelidae.  He  shows  the 
stripes  divided  into  two  in  the  area  between  the  costal  and  subcostal 
tracheae  (Tower,  1906:228,  Figs.  5  to  8,  PI.  XXIV),  which  is  com- 
parable to  the  condition  suggested  in  the  carabids  and  dytiscids  shown 
in  figures  35,  38,  39,  and  40,  plate  IV.  Tower  adhered  to  a  theory  ofteu 
held  by  embryologists,  namely  that  the  base  of  the  wing  is  oldest ; 
further,  that  pigment  appears  first  in  the  base  of  the  elytron  and  pro- 
ceeds to  the  distal  portion  in  accord  with  the  relative  age.  No 
conclusive  evidence  is  brought  forward  to  show  that  the  base  of  the 
elytron  is  actually  oldest,  and  an  examination  of  Tower's  figures  (Tow- 
er, 1906:  156,  Figs.  1  and  2,  7  and  8,  PL  19)  shows  that  the  basal  part 
of  the  elytron  in  some  species  is  not  first  pigmented.  Pigment  begins 
in  the  costal  border  of  the  wing  and  at  the  level  of  the  second  dark 
cross  band  which  he  calls  the  "proximal"  and  which  is  very  common 
in  his  group.  This  is  comparable  to  the  early  stages  in  Cicindela  (Fig. 
111).  The  view  that  pigment  comes  in  first  in  cuticula  over  the  oldest 
tissues  from  the  embryonic  standpoint  seems  not  to  hold  good  in  Cic- 
indela, for  on  this  basis  certain  abdominal  sclerites  would  be  embry- 
onicly  older  than  others  (Figs.  102  to  104,  PI.  VIII),  the  last  abdominal 
segment  older  than  the  first,  and  the  femur  younger  than  the  tibia  as 
well  as  other  peculiarities  shown  in  figures  99  to  103.  The  law  cannot 
be  said  to  hold  good  at  all  in  the  group  under  consideration,  but  rather 
as  has  been  noted  on  page  24,  there  is  an  order  of  post  embryonic 
development  of  adult  organs,  which  coincides  with  pigmentation. 

One  of  the  most  recent  color-pattern  analyses  (Braun,  1914)  shows 
the  pattern  of  Lithocoletes  (microlepidoptera)  to  be  made  up  of  a  mod- 


425]  COLORS  OF  TIGER  BEETLES— SHELF ORD  31 

ication  of  seven  transverse  dark  bands  with  six  transverse  light  bauds 
between  them  (page  161).  The  figure  of  the  hypothetical  pattern  is  in 
general  terras  almost  identical  with  that  shown  for  Ciciudela  and  inde- 
pendently conceived  on  plate  I,  figure  4.  In  this  second  and  third 
light  band  are  represented  by  a  single  wide  one  and  the  fifth  and  sixth 
are  separate  as  two  narrower  bands.  If  the  general  plan  of  longitudinal 
and  cross  bands  in  insect  patterns  is  to  be  accepted  we  must  also  con- 
clude from  the  evidence  presented  that  the  relations  to  trachea,  may  be  - 
reversed,  i.  e.,  the  pigmented  areas  may  lie  immediately  above  the 
tracheae  or  between  them.  In  the  Lepidoptera  pigment  appears  last 
in  the  veins  (JIayer,  1896). 

The  areas  between  the  trachea  may  be  subdivided  into  two  longi-  -W 
tudinal  bands.  The  pigmented  and'unpigmented  bauds  may  also  be 
reversed  iu  position  as  would  appear  to  be  the  case  when  we  compare 
the  usual  cieiudelid  patterns  with  those  studied  by  Tower.  There  is 
no  reason  why  this  should  not  be  the  ease  as  when  markings  are  lost; 
the  pigmentation  which  results  is  often  heavier  than  elsewhere  (Figs. 
135  and  136). 

However  when  one  compares  the  cicindelid  ontogeny  with  the  exist- 
ing patterns  of  other  orders  one  finds  that  they  show  a  series  of  light 
spots  sncli  as  might  easily  correspond  to  the  so-eaUed  cells  or  areas 
divided  by  longitudinal  and  cross  veins  in  a  primitive  insect  such  as  a 
may-fly.  The  may-flies,  stone  flies  and  many  diptera  show  such  an 
arrangement  in  some  parts  of  the  wing.  At  least  it  may  be  safely  con- 
eluded  that  a  pattern  of  faint  spots  is  the  primitive  type  in  Cieindelidae 
if  one  accepts  any  of  the  current  criteria  for  primitive  forms. 

I  start  with  this  type  of  pattern  as  "primitive"  with  a  conscious- 
ness of  the  fact  that  it  would  be  possible  to  proceed  in  entirely  different 
directions  and  from  entirely  different  starting  points  and  make  out 
cases  of  modification  in  definite  direction  fully  'as  plausible  as  the  ones 
here  presented,  provided  only  the  preceding  strong  evidence  is  not  ac- 
cepted. 

On  this  account  it  may  be  well  to  give  the  reasons  for  presenting 
this  matter  of  modification  at  all.  First,  it  is  presented  to  further 
establish  the  contentions  already  made  as  to  the  character  of  the  pattern 
plan  presented ;  secondly,  to  show  that  all  even  the  most  specialized 
types  of  patterns  coxdd  have  been  derived  from  the  generalized  types 
described  above:  thirdly,  to  show  that  there  are  certain  laws  of  modifi- 
cation which  nuist  have  been  very  general  in  tiie  group  and  which  have 
operated  again  and  again  in  the  production  of  the  characteristic  types 
of  patterns. 

Figures  149&,  156a,  and  165,  plate  XII,  show  some  of  the  pat- 
terns in  which  five  nearly  complete  cross  bands  occur;  179  shows  a  very 


32  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [426 

simple  band,  1  with  a  complete,  4  etc.;  185  shows  a  wide  cross  band 
representing  3  and  4.  Figures  149&,  149a  and  156  represent  the  patterns 
of  an  African  species  showing  tliat  variations  are  in  the  direction 
of  greater  obliquity  of  the  cross  mai'kings,  149  approaching  very  closely 
to  148,  wliich  is  a  different  species  and  usually  oblique.  A  third  species 
is  sti'ikingly  oblique  but  still  possessing  the  usual  cross  bars  of  the  group 
of  species.  Thus  in  this  small  group  the  usual  typical  pattern  as  shown 
by  the  general  observations  preceding  is  decidedly  distorted  by  in  a  defin- 
ite dii'ectiou. 

In  figure  165  is  shown  a  type  of  pattern  in  which  the  cross  bands 
are  nearly  vertical  to  the  inner  line  of  the  elytron ;  all  the  spots  present 
fall  in  to  such  bands  as  they  do  in  the  ontogeny  series  (Figs.  112,  113, 
116  and  117,  PI.  IX;  128  and  133,  PI.  X;  143  to  146,  PI.  XI).  In  all 
the  other  figures  on  the  upper  half  of  the  page  the  two  spots 
near  the  elytral  suture  are  not  in  line  with  the  cross  bands.  Evidence  of 
this  will  also  be  found  in  the  ontogeny  series  but  is  less  marked  than 
the  tendency  toward  transverse  bands.  In  165  and  165a  and  in  156  and 
156a,  plate  XII,  the  components  of  crooked  niiddle'  band  are  clearly 
brought  out  in  course  of  variations  in  which  two  bands  may  or  may  not 
be  joined  in  the  stripe  between  the  media  and  radius.  This  tendency 
should  be  noted  as  the  most  characteristic  of  the  genus  Cicindela,  as  there 
is  scarcely  a  group  of  species  as  arranged  on  the  basis  of  pilosity  by 
W.  Horn  in  which  some  one  does  not  show  this  type  of  joining.  The 
breaking  of  the  cross  bands  by  pigment  in  the  line  of  the  media  is  also 
very  characteristic,  but  the  tendency  for  the  spots  to  lie  out  of  the 
lines  with  the  cross  bands  as  interpreted,  is  taken  as  evidence  of  one 
of  the  general  tendencies  to  be  discussed  later.  The  relations  of  the 
characteristic  patterns  to  the  general  plan  is  .thus  made  evident.  An- 
other general  tendency  also  manifested  is  the  tendency  for  the  spots 
shovm  in  figure  156a  to  spread  and  join,  not  in  any  direction  but  in 
definite  lines.  The  figures  to  the  right  and  above  figure  165  illustrate 
the  tendency  for  the  markings  to  join  in  the  line  between  the  pigmented 
areas  of  the  media  and  cubitus  and  for  the  individual  markings  to  still 
retain  their  characteristic  form.  On  this  basis  the  unusual  and  aberrant 
patterns  such  as  150,  151,  152  and  160,  161,  167,  plate  XII,  are  easily 
explained.    In  spite  of  the  extreme  extension  they  are  like  157. 

Figures  170  to  187,  plate  XII,  show  the  patterns  of  species  in 
which  the  longitudinal  striping  lias  been  developed  chiefly-  in  conjunct- 
ion with  some  cross  bands,  but  in  which  there  is  no  suggestion  of  the 
characteristic  middle  band.  Figure  169a  .shows  the  pattern  of  an  Aus- 
tralian species  in  which  all  the  dark  and  light  longitudinal  stripes 
are  represented.  The  dark  area  over  the  subcosta  is  clearly  distinguish- 
able.    In  169a  this  subcostal  dark  stripe  is  reduced  but  still  present. 


427]  COLORS  OF  TIGER  BEETLES— SHELFORD  33 

Fi^ire  169  shows  the  extreme  extension  of  the  white ;  168  shows  a 
reduced  pattern  of  the  same  type;  175,  a  species  with  three  represent- 
ed simple  stripes ;  while  183  has  only  one  stripe ;  170  and  170a  show 
the  variation  in  one  species  in  which  the  middle  white  stripe  may  be 
either  present  or  absent,  and  the  two  posterior  cross  bands  are  present 
and  curved  like  the  end  of  the  elytron.  In  171  the  cross  band  is  broken 
away  from  the  innermost  longitudinal  stripe  in  the  area  of  the  dark 
line  of  the  media  trachea ;  172  shows  a  wide  middle  band  with  the 
longitudinal  stripe  represented  only  in  the  anterior  portion.  Figures 
173  and  17-4  show  types  with  connections  between  an  outer,  unpig- 
mented  side  and  the  central  light  stripe  in  the  center.  Figures  177. 
178,  and  171  show  a  combination  of  the  lateral  stripe  and  the  cross  band 
5.6  ■.  180  to  181a  show  patterns  which  may  have  arisen  from  types  like 
figure  158  above.  Comparing  177,  182,  184,  18-la,  and  176,  one  notes 
varying  lines  of  oblique  connection  to  which  attention  was  called  in 
figures  78  to  87,  plate  VII.  Figures  188  to  231,  plate  XIII,  show 
cross  bands  in  the  Indian-African-Australian  group  in  which  reversed 
obliqueness  of  the  central  band  4  is  developed.    This  obliqueness  is  rare  1 

outside  this  group  except  in  forms  with  a  well  developed  sinuate  middle       V^  / 
band   (e.  g.  Figs.  292  to  298,  PL  XV).     Figures  188  and  188a  show  '  ' 

the  well  developed  cross  bands,  /  and  2.3  being  joined  at  the  side ;  189 
is  similar  and  1  and  2.3  are  joined  obliquely :  190  is  similar  but  reduced. 
198  and  199  are  similar  to  188  but  have  lost  the  last  cross  baud 
and  further  reduction  in  the  same  direction  would  result  in  patterns 
like  197,  205,  and  206.  191  to  196  show  a  series  based  on  the  central 
white  stripe  variously  broken  into  spots  representing  cross  bands.  200 
to  204o  and  213,  plate  XIII,  are  a  series  of  related  species  occurring  in 
India  which  show  an  unusual  oblique  arrangement  and  combination. 
209  an  African  species  belongs  to  a  group  with  pilosity  similar  and 
closely  related  to  the  Indian  group  including  201  to  204a ;  it  shows  the 
same  type  of  obliqueness  in  the  central  marking  as  in  200.  210  to  212, 
plate  XIII,  show  further  modification  of  the  central  band  and  connec- 
tion with  the  oblique  humeral  curve  in  the  line  of  the  central  light 
space.  220  shows  a  slightly  different  trend  of  similar  elements  which 
give  the  combination  in  221  or  220  and  219,  depending  on  the  trend 
taken.  214  to  218  and  222  to  231  show  the  sim])le  patterns  of  cross 
bands  in  which  the  last  and  usually  the  first  are  missing.  232  to  240 
show  combinations  of  markings  resembling  those  just  noted  in  Cicindela, 
in  Therates,  Prothyma  and  Odontochila;  compare  232  and  197,  plate 
XIII ;  233  and  206,  234  and  197 ;  235  and  219 ;  236  and  219 ;  237  and 
188;  238  and  239  with  210  and  213;  and  240  with  188.  There  are 
resemblances  between  patterns  in  other  genera  and  those  in  Cicindela. 
One   note-worthy   African   species    (PI.   XIV,    Fig.   242 — compare 


34  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [42g 

with  209,  C  oscari)  shows  the  umisual  oblique  bending  of  marking 
which  characterized  the  group  noted  above.  This  and  oscari  are  how- 
ever the  only  species  in  which  it  occurs  and  the  group  to  which  it 
belongs  is  similar  in  pilosity  to  the  Indian  groups  just  described.  This 
particular  one  stands  in  closest  relation  to  those  shown  in  plate  XII, 
figures  170,  llOa.  and  171.  It  is  introduced  here  because  at  the  outer 
margin  its  markings  represent  2,  5,  and  6  with  the  almost  universal 
central  or  fourth  absent,  except  at  the  innerside  where  4  seems  to  be 
present  and  obliquely  joined  to  5.  241,  a  and  b  show  a  pattern  in  which 
5  and  6  are  present  while  4  is  wanting  except  for  a  few  small  dots. 
This  speciesi  appears  to  show  a  tendency  to  double  longitudinal  lines. 
243  shows  a  second  African  species  in  which  there  is  a  tendency  to 
double  stripes  but  the  central  cross  band  represented  at  the  margin. 
The  patterns  show,,  in  fig\ires  244,  244ff,  245  and  plate  XIV  are  of 
especial  interest  because  the  division  of  the  second  cross  band  in  those 
numbered  5  and  4  in  the  preceding  figures  are  both  represented  as  spots. 
This  is  of  rare  occurrence,  the  more  usual  arrangement  being  like  that 
shown  in  figure  251.  Figures  248  a  and  6  show  the  double  longitudinal 
stripes  of  an  African  species,  a  ease  similar  to  those  illustrated  above 
in  which  one  of  the  types  of  variation  is  in  the  direction  of  the  spreading 
of  the  white.  Figures  247  and  247«  show  the  joining  of  such  markings 
as  occur  in  246  and  259  to  make  a  central  longitudinal  stripe. 

Figures  257  to  261,  plate  XIV,  show  unusual  patterns  of  spots, 
which  fall  into  the  usual  cross  bands  on  the  whole,  but  those  in  the 
inner  margin  of  the  elytron  are  usually  shifted  out  of  line.  Figures 
262  to  280  show  various  directions  of  reduction  of  markings  in  patterns 
of  the  type  shown  in  figures  266,  274  and  274o.  Those  at  the  left  show 
the  loss  of  the  central  stripe  and  those  to  the  right  the  loss  of  the  inner 
markings,  entirely  or  in  part.  281,  282,  283  show  the  extensions  and 
obliquity  in  the  type  pattern  showm. 

Plate  XVI,  figures  292  to  306,  show  the  American  species  in  which 
cross  bauds  5  and  6  are  separated  as  seen  in  289,  294,  293,  etc.  The 
general  tendency  is  for  the  markings  to  disappear  from  the  anterior  to 
the  posterior  end. 

The  component  parts  of  the  oblique  vitta  of  some  species  of  the 
Mexican  group  is  illustrated  by  figures  311  to  313  and  319  and  similar 
components  making  a  somewhat  different  vitta  in  291,  296a,  and  297. 
Figures  315  to  328  show  patterns  in  which  the  last  or  apical  (7)  cross 
band  is  missing  or  in  which  variations  arise  in  which  it  is  reduced. 

Figures  329  to  355,  plate  XVI,  show  the  species  chiefly  Eurasian, 
a  few  American,  in  which  bands  5  and  6  are  present  and  separate,  the 
former  illustrated  by  a  marginal  spot  behind  the  center.  Figure  347 
shows  a  narrow  longitudinal  stripe  extending  forward  from  the  spot 


429]  COLORS  OF  TIGER  BEETLES— SHELF ORD  35 

near  the  apex,  this  is  an  unusual  variation  in  a  race  of  a  European 
species.  Figures  361  to  363  show  a  tendency  in  certain  species  for  the 
formation  of  a  vitta  in  the  space  between  the  subcostal  and  radius 
(tracheae).  Figure  364  shows  an  unusual  joining  of  the  marking  of  a 
specimen  of  C.  limbalis  loaned  by  Professor  H.  F.  Wickman,  in  the  space 
between  tlie  subeosta  and  the  radius,  though  the  species  rarely  lias  the 
markings  joined  and  when  so  not  in  this  line  (A)  but  in  line  a.  365 
shows  an  aberrant  marking  in  the  central  part  of  the  elytron  of  C. 
campesiris,  which  is  a  common  European  species.  366  shows  the  darker 
spots  about  the  white  marking  iu  a  closely  related  species.  370  to  377 
show  the  patterns  of  other  genera ;  compare  370  and  362 ;  371,  and  185 ; 
372  with  367 :  373  with  367. 

Figures  402  to  478  are  presented  to  show  series  of  unusual  com- 
binations illustrated  by  the  Indo-Australian  group  of  species.  378 
shows  a  marking  projecting  backward  composed  of  the  band  2.^  and 
the  longitudinal  part  of  the  pattern  plan  whicli  lies  between  the  media 
and  the  cubitus  (tracheae)  ;  the  lettered  number  of  the  same  species 
shows  the  extinction  of  the  white.  386  shows  an  miusual  tj'pe  of 
pattern  in  which  the  curve  appears  to  rise  in  cross-band  J  while  the 
light  sti'ipe  between  the  media,  and  cubitus  is  obliquely  joined  in  the 
anterior  end  to  the  central  spot  at  the  elytral  base.  Extension  of  the 
white  is  common  in  variations  in  this  group  (383,  384,  385),  379  to  382 
show  a  combination  between  the  middle  band  and  the  central  basal 
spot  and  .spreading  of  the  white.  389  shows  a  similar  pattern  but  with 
the  joining  in  the  cross-band  2.^  and  extension  of  the  white.  387  and 
396  are  somewhat  generalized,  representative  of  the  type  in  question 
whicli  with  slight  modifications  may  have  led  to  the  397  and  398  series 
of  patterns  (/)  or  by  extension  tq  the  392-395a  series  and  400.  The 
balance  of  the  illustrations  show  the  unusual  patterns  of  the  Ciciiidelas 
both  reduced  to  a  single  marginal  stripe  and  in  full  form.  Most  of  the 
species  represented  are  from  Australia  and  New  Zealand. 

Figures  422  to  454,  plate  XVIII,  show^  the  imusual  marking  of 
Cicindelas  with  slight  distortions,  but  all  the  patterns  belonging  to 
groups  of  species  which  show  a  strong  tendenc}-  in  the  chief  representa- 
tives to  varj'  in  the  direction  of  nearly  all  white  individuals.  The  irregu- 
lar and  oblique  marking  in  figures  422  and  423,  representing  two  South 
American  species,  shows  an  unusual  type  of  degeneration  of  the  system. 
The  peculiar  irregular,  branched  and  scattered  character  of  the  mark- 
ings of  several  groups  shown  indicates  the  breaking  up  of  the  system 
of  marking  which  has  been  designated  as  the  type  upon  which  they  are 
based. 

The  different  species  are  characterized  by  peculiar  turns  forward 


36  JLLIXOIS  BIOLOGICAL  MOXOCRAPHS  [430 

of  certain  markings.  Compare  for  example  the  anterior  eross-baud 
(humeral  lunule)  of  436  and  427;  one  is  turned  forward  with  a  char- 
acteristic curve,  the  other  backward.  This  is  a  difference  between  the 
two  species  which  holds  good  throughout  all  the  individuals.  The 
extension  of  the  white  shown  is  clearly  associated  with  a  degeneration 
of  some  of  the  chief  tracheal  trunks. 

From  this  large  series  of  figures  we  must  not  permit  ourselves  to 
judge  that  all  types  of  pattern  are  equally  common  and  equally  general 
in  the  species  of  the  genus.  Figures  329  to  333,  and  figures  130  and  131 
show  the  commonest  and  most  characteristic  types  in  the  genus  which 
are  universally  distributed  and  make  up  vast  majority  of  the  grand 
total  for  the  world. 

Th|s,  the  first  definitely  directed  tendency  in  the  group,  has  been 
the  union  of  spots  to  form  the  characteristic  markings  of  the  group 
shown  in  figure  49,  plate  V,  as  combination  of  Al,  A2,  B2,  or  B3  to 
make  the  humeral  lunule  so  called,  of  A4,  B4,  and  B5  to  make  the  so- 
called  middle  hand,  and  of  A6  and/  to  make  the  apical  lunule  of  the 
taxonomists  of  the  group.  If  these  three  types  of  joining  are  granted 
as  the  first  directive  principle  entering  into  the  make  up  of  the  patterns 
of  the  group  it  must  also  be  noted  that  it  does  not  apply  to  the 
majority  of  species  in  nine  of  Horn's  groups  (XXVII-XXXVI)  includ- 
ing 40  species  (Figs.  188  to  215  and  220  to  231,  PI.  XIII).  A  few  patterns 
Avith  middle  band  and  apical  and  humeral  lunules,  and  which  have 
three  spots  in  the  basal  and  anal  portion  of  the  elytron,  are  included  in 
these  groups  and  differ  from  most  others  of  similar  components  in  the 
presence  of  these  spots  (Figs.  273  and  274,  PI.  XIV,  and  163  and  164, 
PI.  XII).  These  few  are  the  only  rei^resentatives  which  show  this  char- 
acteristic middle  band  humeral  audi  apical  lunule.  It  applies  to  only 
16  species  of  the  Horn's  pilosity  groups  XVIII  to  XXII  which  include 
66  species  in  Africa  (Figs.  147  to  149fl,  PL  XII;  269,  PI.  XIV;  156, 
PL  XII;  265,  241  to  272,  278  to  280,  PL  XIV).  Of  the  figures  cited, 
156  and  265  are  of  the  most  primitive  type  and  266,  267,  275  and  278 
show  modifications. 

If  we  grant  the  majority  of  the  remaining  500  species  show  these 
characteristics  as  variations  or  that  they  may  for  purposes  of  discus- 
sions be  assumed  to  have  been  derived  from  forms  which  did  have  the 
three  characteristic  markings  we  note  that  in  general  the  patterns 
except  those  mentioned  above  fall  into  two  parallel  series  one  witliout 
the  spots,  including  the  majority  of  species,  and  the  other  with  them, 
including  a'  comparatively  small  number  of  species.  Those  with  the 
three  spots  are  confined  chiefly  to  the  land  directly  bordering  the  Indian 
Ocean  being  especially  numerous  in  Africa  and  India.  Spots  may  be 
wanting  in  some  variants  of  such  species  as  cscheri  (Figs.  267  and  268) 


431]  COLORS  OF  TIGER  BEETLES— SHELF ORD  37 

aud  monteiroi  (Figs.  276  and  277).  These  belong  to  groups  which  nor- 
mally have  them,  but  thej'  almost  never  occur  in  groups  which  do  not 
show  them  in  a  majoritj^  of  members.  Considering  the  compoients  of 
the  three  spots,  the  anterior  central  spot  {Bi,  Fig.  49,  PI.  V)  is  a  part 
of  the  basal  cross  baud  /  clearly  shown  in  figure  179.  The  anterior  one 
in  stripe  C,  figure  48,  plate  V,  appears  to  be  a  fusion  of  spots  Ci  and 
C2  and  the  posterior  one  of  C3  and  C4  as  a  rule,  though  sometimes  the 
posterior  one  is  C4  and  the  anterior  one  Cl.2,  figure  165.  There  is  a 
tendency  indicated  by  variation  to  drop  oiit  these  markings  in  many 
species.  In  flexuosa  usually  C  1.2,  i.  e.,  the  basal  sutural  spot,  is  first 
to  go.  In  others  this  is  not  true  as  a  nde,  as  shown  in  261,  276,  277 
and  280.  On  the  other  hand  there  is  no  species  in  which  these  are 
present  and  other  markings  absent.  These  facts  indicate  that  these 
spots  show  a  tendency  to  disappear  first,  leaving  the  types  of  pattern 
without  them,  ilore  rarely  they  may  unite  to  form  a  band  which  may 
persist  in  the  extremely  modified  forms,  figures  151,  160,  and  167.  One 
of  the  characteristic  types  of  marking  which  seems  to  belong  to  almost 
the  entire  group  showing  the  typical  middle  band,  is  the  oblique  shift- 
ing of  the  cross  band  which  makes  the  humeral  lunule. 

The  tendency  toward  obliqueness  of  the  middle  band  of  the  typical 
forms  seems  quite  general  in  many  groups  but  by  no  means  iiniversal, 
and  is  sho\^m  by  some  species  in  all  the  groups,  and  hence  is  illustrated 
in  all  the  groups  of  figures :  157,  163,  222.  227,  273,  276.  288,  299,  451, 
33.5,  336,  342,  411,  and  417. 

In  other  groups  another  tendency  seems  to  be  present,  namely  to- 
ward a  sharp  forward-bent  angle  on  the  middle  band  (Fig.  482)  figures 
209,  206,  and  many  others  in  which  the  usual  combinations  have  not 
been  affected  are  sho^vn  in  plate  XIII.  On  the  other  hand  scarcely  a 
species  in  plate  XII  shows  this  tendency  except  figure  150.  Figures 
292  and  293,  plate  XV,  339,  plate  XVI^i  and  others  related  show  the 
same  tendencj'.  It  is  shown  in  the  patterns  of  the  Australian  group 
(Figs.  394  to  396,  PI.  XVII)  where  a  middle  band  involving  different 
elements  occurs,  and  is  particularly  conspicuous  and  characteristic  in 
some  of  the  Mexican  and  South  American  species  (Figs.  428  to  434,  PI. 
Xr\"III)  where  it  is  the  chief  distinguishing  feature.  In  the,  group  as 
a  whole  the  most  striking  tendency  is  for  the  markings  to  disappear, 
beginning  in  the  proximal  anal  region  of  the  elytron  and  usually  leaving 
the  more  posterior  distal  markings  present.  But  to  this  tliere  are  many 
exceptions  in  which  the  central  marking  on  the  elytron  is  the  only  one 
left.     (See  figures  255,  plate  XIV;  222  to  231,  plate  XIII;  and  206.) 

Another  tendency  manifested  in  many  species  is  the  extension  of 
the  white;  it  is  seen  to  crop  out  in  all  groups  from  any  starting  point 
which  is  in  existence  and  to  proceed  from  tlie  spots  characteristic  of 


38  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [432 

the  group,  in  the  direction  of  general  concentric  extension  in  wliich 
the  original  type  of  pattern  may  be  recognized  (Figs.  160,  167,  169,  and 
181,  PL  XII ;  204,  204a,  196,  PI.'XIII ;  378  to  437,  Pis.  XVII  and  XVIII) . 
Thus  one  who  inspects  the  figures  as  arranged  is  inijiressed  with 
the  fact  that  there  are  a  great  many  directions  in  which  patterns  have 
been  modified  and  these  figures  are  numerous  and  intentionally  substi- 
tuted for  less  satisfactory  descriptions.  The  material  afforded  by  the 
600  or  more  species  is  rich  iu  possibilities  and  excels  in  this  respect  the 
butterflies  of  Eimer  or  pigeons  of  Whitman. 

EXPERIMENTAL   MODIFICATION   OP  PATTERNS 

To  test  the  laws  of  modification  of  the  typical  patterns  of  Cicindela 
larvae  of  several  species — C.  tranqucharica,  rcpanda,  hirticollis,  lim- 
balisylepida,  and  lecontci — were  subjected  to  low  temperature,  high  tem- 
perature, and  moist  and  dry  conditions.  The  temperature  was  raised 
about  10  degrees  C.  above  that  encountered  in  the  normal  outdoor  life 
history.  The  experiments  were  carried  on  in  the  apparatus  sho^^^l  in 
figure  455,  plate  XXIX,  and  described  in  connection  therewith. 

The  larvae  were  put  into  the  high-temperature  (near  37°,  1906; 
40°C,  1905)  about  May  15.  They  were  placed  in  a  lamp  chimney  con- 
taining fine  sand.  The  apparatus  as  arranged  gave  2°  to  4°C.  higher 
temperature  at  the  top  than  at  the  bottom.  The  average  of  the  two 
was  used  in  computing  the  mean.  Temperatures  were  taken  twice  a  day 
as  a  rule.  The  temperature  rose  each  day  as  the  sun  shone  on  the 
eases  so  that  during  tlie  hottest  weather  daily  maxima  in  soil  temper- 
ature went  to  40  to  42  degrees  at  times. 

The  results  of  the  experiments  on  C.  tranqucbarica  so  far  as  the 
patterns  are  concerned  are  shown  in  figure  456  a  to  g,  plate  XX,  and  457 
ato&,458,459  and  460;these  should  be  compared  with  control  456 o' to &', 
w',  457  a'  to  e',  w'  and  458  a'h'.  A  comparison  of  these  experiments 
with  their  control  and  the  representative  of  the  forms  collected 
in  the  field  from  the  same  generation  shows  that  in  tlie  controls  the 
normal  middle  band  reaches  to  the  margin  of  the  elytron  where  it  is 
expanded  in  the  line  of  the  longitudinal  band  a  A;  the  longitudinal  part 
is  parallel  with  the  anal  side  of  the  elytron ;  the  middle  band  is  hooked 
at  the  end  or  turns  into  a  horizontal  position  in  compliance  with  the 
normal  direction  of  the  transverse  band  from  which  it  is  derived.  The 
humeral  lunule  is  usually  hooked.  The  angle  iu  the  middle  band  is  a 
right  angle  and  there  is  a  forward  extension  of  the  middle  band  at  the 
angle. 

The  patterns  which  result  from  tlie  experimental  conditions  almost 
without  exeejition  differ  from  the  control  in  the  following  respects: 


433]  COLORS  OF  TIGER  BEETLES-SHELFORD  39 

1.  The  humeral  lumile  is  usually  without  any  enlargement  at  the 
end  suggesting  au  expansion  in  the  place  of  spot  Bj  and  j. 

2.  The  middle  baud  is  withdrawn  from  the  margin  in  all  cases 
and  in  only  one  case,  figure  556  g,  is  there  auy  longitudinal  extension. 

3.  The  angle  of  the  middle  band  is  always  less  acute  and  the  for- 
ward extension  less  pronounced. 

4.  The  longitudinal  portion  of  the  middle  band  is  oblique  to  the 
anal  or  inner  margin  (suture)  of  the  elytron. 

5.  The  end  of  the  middle  baud  is  not  hooked  but  rounded,  and 
rarely  even  parallel  with  the  transverse  bands. 

A  close  examination  of  the  marking  of  the  experimental  individuals 
show  that  there  is  correlation  in  all  the  respects  in  which  the  middle 
baud  is  modified,  in  general  the  most  oblique  middle  band  is  almost 
withdrawn  from  the  margin  and  shows  least  hook  at  the  end. 

Figure  461  shows  au  unusual  type  of  marking  and  of  modification, 
the  most  reduced  marking  in  specimens  of  C.  linibalis  subjected  to  the 
same  experimental  conditions  as  the  tranquebarica  shown  above.  The 
usual  type  of  modification  which  is  quite  general  in  experimental  speci- 
mens has  the  longitudinal  portion  of  the  middle  band  shortened.  It  is 
also  more  oblique  and  thus  less  like  the  simple  type.  The  middle  bands 
of  these  specimens  approach  those  of  the  variety  splcndida  (Kansas). 
They  represent  a  more  extreme  modification  of  the  simple  type  than 
the  experimental  middle  bands  of  specimens  of  C.  tranquebarica.  The 
markings  in  two  out  of  about  twenty  individuals  (Fig.  461)  surviving 
the  liigh  temperature  showed  a  sharp  bend  for\\ard.  This  is  the  reverse 
of  the  usual  tendency  in  the  purpurea  group  but  is  a  strong  tendency 
in  some  other  species  shown  in  plates  XIII  and  XV.  One  indi^^dual 
out  of  several  hundred  collected  from  the  habitat  in  question,  reared 
as  controls,  and  reared  for  ontogeny  showed  this  character.  Apparently 
the  tendency  to  respond  by  a  sharp  forward  bend  is  little  developed  in 
purpurea. 

Figure  463  a  to  d,  464  a  to  c,  and  466  show  the  patterns  resulting 
from  the  high  temperature  experiment  witli  C.  Iccontei  while  466  a'  to 
c'  and  467  u'',  x',  y',  and  z'  show  the  conti'ol  which  survived  and  the 
range  of  variation  in  a  series  of  specimens  collected  from  the  same 
area  from  which  the  larvae  for  the  experiments  were  obtained.  First 
of  all  the  high  temperature  experiments  show  patterns  with  reduced 
markings.  The  markings  shown  in  463r;  are  joined  in  a  way  which  rarely 
or  never  occurs  in  the  stock  from  which  they  were  collected  and  which 
is  on  the  other  hand  characteristic  of  the  varieties  of  this  species  which 
occur  on  the  Atlantic  coast.  Also  463rf  shows  a  pattern  which  is  smaller 
in    markings    than    auy   that   have    ever   been  collected  near  Chicago, 


40  ILLI.XOIS  BIOLOGICAL  MOXOGRAPHS  [434 

467  II  representing  the  smallest,  ■which  makes  the  marking  of  463  un- 
doubtedly reduced  by  experimental  condition. 

Figures  465  a  to  6  show  experiments  in  which  the  larvae,  pupae 
were  iced  from  the  beginning  of  the  pupal  stage;  all  either  by  remark- 
able accident  or  through  the  effects  of  the  experimental  conditions  show 
the  widest  type  of  markings;  a  third  specimen  was  only  slightly  modi- 
fied. In  465&  the  form  of  the  end  of  the  elytron  is  rounded  in  an 
unusual  way  and  the  surface  appearance  of  the  entire  body  and  the 
elytron  are  different  from  the  normal  types. 

Figure  46Sa  and  w'  show  the  type  of  modification  occurring  in 
experiments  on  C.  hirticoUis.  The  middle  band  is  modified  as  follows: 
the  hooks  aud  angles  are  rounded,  the  transverse  part  which  usually 
turns  forward  and  has  a  sharp  angle  as  in  468  w'  is  oblique  in  the 
opposite  direction.  These  modified  patterns  are  identical  with  those  in 
southern  and  western  localities.  This  modification  is  of  the  same  kind 
as  that  in  C  tranqueharica  and  C.  purpurea. 

Thus  it  is  evident  that  C.  tranqueharica,  hirticoUis,  and  lecontei 
may  be  modified  in  structure  and  pattern  by  high  temperature  during 
the  pupal  and  prepupal  stages.  Experiments  performed  on  C.  repanda, 
Icpida,  and  punctidata  show  no  such  modification,  or  pattern  modifica- 
tion of  any  other  type  so  far  as  has  been  noted.  Specimens  stimulated 
by  al  temperature  of  37° C.  in  the  fall  and  forced  through  the  winter 
were  modified  only  in  case  of  the  specimens  which  emerged  early, 
January  1.  Specimens  which  emerged  in  the  spring  earlier  than  the 
normal  were  not  modified.  One  specimen  of  C.  hirticoUis  (Fig.  566, 
PL  XXXI)  coming  through  without  any  winter  was  very  much  smaller 
than  the  normal.  A  specimen  of  C.  lecontei  shown  in  color  plate  XXIX, 
figure  556,  was  different  in  form,  the  abdomen  being  broadest  at  a 
point  not  usual  for  lecontei. 

One  of  the  patterns  of  tranqueharica  produced  in  this  waj*  (Fig. 
459)  was  one  of  the  most  striking  modifications  obtained. 

Thus  so  far  as  the  species  which  show  modification  are  concerned 
the  modification  appears  to  be  in  definite  directions  and  the  modifications 
of  C.  tranqueharica,  C.  hirticoUis,  and  C.  limhalis  are  in  the  general 
direction  in  which  the  modification  of  the  pattern  plan  has  proceeded 
in  many  patterns  which  have  deviated  from  it  in  course  of  their  evolu- 
tion. The  experimental  results  further  show  a  basis  for  the  interpre- 
tation of  the  geographic  variation  of  the  group  which  is  our  next  topic 
for  consideration. 

GEOGR.\PHIC    VARIATION    OF   PATTERNS 

C.  tranqueharica,  very  widely  distributed  in  North  America, 
(PI.   XXII)    shows   great  variation   in   color   and   markings,   but   the 


435]  COLORS  OF  TIGER  BEETLES— SHELFORD  41 

extreme  forms  are  comparatively  rare  and  eoufiiied  to  the  Pacific  states. 
Plate  XXI  shows  the  classes  into  which  the  patterns  of  this  species  may 
be  divided  and  their  distribution.  The  graphs  represent  the  distribu- 
tion of  the  per  cent  of  classes  shown  by  the  figures  below  for  specific 
localities.  It  will  be  noted  that  tj^pes  g  and  h  which  correspond  in 
middle  band  characters  occiu"  occasionally  as  extremes  especially  in 
Kansas  and  Texas  localities,  while  west  of  the  rockies  where  the  summer 
and  springs  are  dry  and  favor  high  soil  temperatures  these  tyY)es  are 
fairly  common.  This  type  of  marking  with  middle  band  reduced  at 
the  margin  makes  up  a  considerable  percentage  of  the  individuals 
collected  at  Hagermau,  Idaho ;  San  Bernardino,  California ;  Provo,  Utah ; 
and  Las  Vegas,  Nevada ;  but  they  are  nowhere  the  dominant  type.  In 
certain  Nevada  localities  the  retirement  of  the  middle  band  appears 
to  begin  at  the  inner  end  and  the  withdrawal  from  the  margin  follows 
only  in  very  reduced  types.  The  type  with  the  middle  baud  with- 
drawn occurs  in  southern  and  western  localities.  Twelve  per  cent  of  the 
specimens  from  central  Texas  show  middle  bands  like  those  modified 
in  experiment.  On  the  whole  there  is  a  correspondence  between  high 
soil  temperature  and  the  reduced  tj'pe  of  markings  which  accords  with 
the  experimental  results. 

Plate  XXIII  shows  the  geographic  variation  of  C.  scutellaris  and 
its  varieties  ranked  as  aberrations  by  Horn.  The  series  of  classes  shown 
beginning  at  the  extreme  left  are  from  the  northern  portion  of  its 
range  in  New  England;  passing  to  the  right  are  shown  verj-  reduced 
markings  at  Raleigh,  and  very  rarely  any  markings  at  all  at  Mobile 
and  in  Texas  localities  or  points  in  western  and  west  central  states: 
Oklahoma,  Kansas,  Nebraska,  and  South  Dakota,  Colorado  and  New 
ilexico.  In  all  localities,  however,  on  and  east  of  the  Missouri  River 
in  the  central  states,  there  is  a  noticeable  increasing  in  the  size  of  mark- 
ings as  we  pass  to  more  northerly  localities  and  to  more  easterly  local- 
ities as  fai*  as  Chicago.  East  of  Chicago  the  marking  of  specimens 
from  along  the  lake  shores  are  not  larger  than  those  taken  at  the  south 
end  of  Lake  Michigan.  As  will  be  seen  from  the  graphs  (PI.  XXIII) 
the  range  of  variation  is  least  in  the  gulf  states  localities  where  the 
markings  are  most  reduced. 

There  is  further  a  noteworthy  difference  in  the  Mississippi  Valley 
and  Atlantic  Coast  forms.  The  humeral  dot  {ai,  Fig.  48,  PI.  V)  is 
never  present  and  the  so-called  posthumeral  dot  {A3.3,  Fig.  48,  PI.  V) 
is  seldom  so  except  in  the  more  northern  localities  and  is  never  large 
when  present.  It  is  never  joined  to  the  middle  band  {A4,  B4).  The 
markings  are  massed  in  the  posterior  half  of  the  elytron  on  the  costal 
margin.  In  the  forms  from  Missouri  River  localities  and  eastward  the 
humeral  dot  is  usually  present — always  present  in  the  more  eastern 


42  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [436 

form — and  its  absence  is  associated  with  extreme  reduction  of  the 
markings  in  general.  Thus  patterns  made  up  of  a  row  of  dots  on  the 
costal  side  of  the  elytron  are  the  most  numeroiis  in  Iowa  localities  and 
probably  those  just  east  of  the  Missouri  River.  Thus  the  selected 
classes  of  individuals  are  geographic  in  their  relations  and  hence  true 
classes.  Further  evidence  for  this  statement  is  shown  in  plate  XXXIV 
where  the  color  differences  are  indicated,  showing  that  the  immaculate 
forms  are  further  divided  into  races  on  the  basis  of  color.  Those  of 
the  humid  southern  states  are  green,  and  those  of  the  western  steppe, 
with  its  dry  early  summer  following  early  spring  rains,  are  red. 

In  full  accord  with  the  experimental  results  cited  above  are  certain 
differences  in  patterns  of  two  localities  from  which  collections  were 
made  often.  The  larvae  used^  in  experiments  were  collected  from  a 
point  just  north  of  the  village  of  Miller,  Indiana,  from  a  small  area  of 
oak  dimes  about  an  acre  in  extent.  Adults  were  collected  from  this 
same  locality  dviring  several  years  at  various  times  in  the  season  and 
differences  in  color  and  pattern  were  noted.  Graph  10  is  the  distribu- 
tion of  classes  in  200  individuals  belonging  to  the  generations  of  1904 
and  1905.  This  same  graph  is  repeated  above  on  a  smaller  scale  with 
graph  11  added,  which  shows  the  distribution  of  classes  in  .51  speci- 
mens collected  from  the  same  area  in  April,  1906.  Graph  12  shows  the 
distribution  of  classes  in  a  series  of  60  specimens  collected  in  the  north- 
western part  of  Gary,  (600  ft.)  (Pine  Station,  Indiana,)  in  April, 
1906,  showing  the  modal  class  to  be  o  instead  of  q  and  a  small  percent- 
age of  individuals  with  markings  joined.  Graph  13  shows  the  distribu- 
tion of  classes  in  a  series  of  37  specimens  collected  in  September,  190S, 
in  which  the  same  difference  is  shown.  A  difference  in  the  distribution 
of  classes  is  indicated  by  a  comparison  of  Graphs  12  and  13.  These 
differences  are  striking  for  one  who  is  familiar  with  them.  The  dif- 
ferences between  the  Gary  and  the  Miller  locality  were  noted  while 
collecting  the  species  in  the  two  localities  during  several  years.  The 
specimens  collected  in  Gary  showed  those  with  markings  joined  as  very 
rare.  The  entire  series  from  the  Gary  locality  show  the  same  thing. 
There  are  also  similar  differences  from  generation  to  generation,  in  the 
catches  from  Miller.  The  difference  in  the  conditions  at  Miller  and  in 
the  Gary  locality  is  striking  particularly  during  the  larval  and  pupal 
periods.  The  area  in  Gary  is  covered  with  scattered  pines  and  in 
places  from  which  some  of  the  specimens  were  collected  cottonwoods 
occur.  The  area  is  one  of  lake  sand  on  which  cottonwoods  grow  up 
and  are  succeeded  by  pines  and  the  pines  by  oaks.  The  Miller  locality 
is  an  oak  dune  area  with  well-established  growth  of  oaks.  One  mile 
south  of  the  Gary  locality  are  oak  covered  ridges.  Specimens  from 
jiere  are  of  the  usual  type  taken  in  the  Miller  locality.     Many  of  the 


437]  COLORS  OF  TIGER  BEETLES—SHELFORD  43 

nines  had  been  cut  off  the  pine  belt  in  Gary  wliere  my  specimens  were 
collected.  It  is  about  as  open  as  the  cottonwood  belt  where  evaporation 
from  the  porous  cup  atmometer  is  about  twice  that  of  the  oak  dunes 
in  which  the  ]Miller  specimens  were  collected.  The  soil  temperature 
goes  very  high  in  the  Gary  locality. 

Distance  below  Temperature  in  degrees  G 

surface  Air  36  C 

1 1-4  cm.  47 

3-4  cm.  38 

8-9  em.  35 

10-11  cm.  33 

12-13  cm.  32 

17-18  cm.  30 

These  forms  pupate  at  a  depth  of  15  cm.  and  thvis  at  a  tempera- 
ture of  31°C.  on  the  warmest  days.  The  temperatures  in  the  shade  in 
oak  covered  sand  dunes  are  much  lower  being  about  27°C.  under  the 
same  conditions. 

Plate  XXV  shows  the  division  of  the  various  subspecies  of  C.  pifr- 
purca  into  classes.  Here  the  primary  division  of  the  group,  shown  in 
the  immaculate  form  in  the  center  of  the  group  which  is  ver^v  rare,  is 
an  habitudinal  one — those  at  tlie  left  are  the  patterns  of  a  series  of  races 
which  inhabit  level  ground  usually  among  scattered  vegetation.  To  tlie 
right  are  tliose  that  occupy  steep  banks,  particularly  clay  banks.  Classes 
a  and  b,  cimarrona,  and  t,  10  guttata,  do  not  appear  to  be  so  differentiated 
and  accordingly  the  graph  perhaps  should  have  been  revei-sed  with  the 
generalized  patterns  in  the  center,  though  further  investigation  would 
be  necessary  to  determine  this.  The  present  arrangement  is  based  on 
resemblances  between  the  two,  cimarrona  and  those  at  the  left,  and  C. 
10  guttata  and  those  at  the  right.  The  distribution  of  the  two  gi-oups 
shown  at  the  right  and  the  left  of  the  center  are  shown  in  figures  471(7 
and  472. 

If  one  notes  the  localities  represented  by  the  graplis  showing  the 
distribution  of  classes,  it  is  evident  that  there  is  no  striking  difference 
in  tlie  distribution  of  classes  in  Puget  Sound,  Massachusetts,  and  Color- 
ado. The  modal  ela.ss  for  Manitoba,  Topeka,  and  Chicago,  is  tlie  same. 
This  goes  to  indicate  that  the  main  line  of  separation  is  habitudinal 
rather  than  geographic. 

Similar  relation  could  be  shown  for  other  species.  The  main  differ- 
ences in  patterns  are  primarily  associated  either  with  different  local- 
ities usually  separated  geograpliically,  or  witli  differences  in  habitat 
preference. 

The  figures  on  plate  XXVI II   (Figs.    473    to    536)    are    arranged 


44  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [438 

in  parallel  lines  of  similar  patterns.  Thus  figures  473  to  485  are  pat- 
terns of  C.  iranqucharica  similar  to  those  sho^^-n  in  figures  486  to  494, 
exceiJting  481  and  483  which  are  diiferent  species  closely  related  to  C. 
tranquebarica.  In  figures  486  to  490  are  shown  a  series  representing 
the  typical  patterns  in  C.  scutellaris;  it  will  be  noted  that  these  parallel 
tliose  of  C.  tranquebarica  with  most  reduced  markings.  Also  figures 
491  to  496  show  the  pattern  of  tlie  Great  Basin  group  of  species  and 
varieties  to  which  C.  fulgida  is  closely  related.  These  parallel  some  of 
the  patterns  of  C.  tranquebarica  and  are  in  turn  paralleled  by  those 
of  other  species.  Concentric  extension  of  the  white  likewise  character- 
izes the  patterns  of  the  group.  Figures  497  to  501  show  a  series  of 
patterns  in  C.pulchra  which  are  roughly  parallel  to  tliose  of  C.  tranque- 
barica and  very  closely  parallel  to  those  of  C.  scutellaris.  The  com- 
monest pattern  of  this  species  is,  however,  figure  498;  499  and  501 
being  rare  and  collected  only  near  Alpine,  Texas. 

Figures  503  to  505  show  the  series  of  patterns  of  C.  longilabris 
which  parallel  the  patterns  of  other  species  shown  above  and  below. 

Figures  506  to  518  show  a  remarkable  and  long  series  of  patterns 
of  purpurea'  parelleling  the  entire  tranquebarica  series  without  the 
addition  of  other  species.  The  entire  series  is  however  different  than 
the  other  series  especially  different  from  the  tranquebarica  series  be- 
cause of  the  short  humeral  lunule  which  always  stops  with  spot  A2.3 
while  that  of  C.  tranquebarica  is  made  up  of  A2  and  B3  in  oblique 
combination  (see  Fig.  49,  PL  V).  Figures  522  to  527  show  the  markings 
of  the  C.  sexguttata  group  which  parallel  those  of  the  other  groups  quite 
well  throughout  a  series  of  five  types.  Figures  528  to  536  show  a  series 
of  types  belonging  to  five  closely  related  species.  The  patterns  at  the 
extreme  right  show  extension  of  the  white  which  appears  to  have  occur- 
red as  a  tendency  taken  at  an,y  point  in  the  series  represented;  thus 
figures  520  and  521  belong  with  488  and  to  the  same  species.  Figure 
519  belongs  with  531  and  represents  a  different  type  of  extension. 

While  a  general  parallelism  is  shown  by  the  series  of  patterns, 
there  is  also  a  characteristic  series  of  small  differences  belonging  to  the 
usual  types  of  most  species.  This  indicates  that  specific  cliaracters 
in  the  color  patterns  are  matters  of  detail  and  am^  definitely  directed 
specific  or  racial  tendencies  woiild  have  to  be  based  on  a  consideration 
of  such  details  rather  than  the  general  plan  of  the  pattern  and  the 
general  parallelism  shown  in  the  group  of  figures  just  discussed.  While 
specific  patterns  are  often  very  closely  parallel,  one  who  is  very  familiar 
with  them  can  identify  the  species  from  a  single  elytral  pattern  in  the 
vast  majority  of  cases. 

Considering  the  pattern  of  the  rest  of  the  group,  represented  in 
figures  473  to  537,  C.  formosa  and  its  varieties  is  distributed  on  the 


439]  COLORS  OF  TIGER  BEETLES— SHELFORD  45 

Atlantic  coast  and  foi-  some  distance  inland  in  llassaehusetts  to  Mary- 
land where  the  markings  are  of  the  tj-pe  shown  in  figure  532  and  slight- 
ly wider  with  the  all  joined  at  the  side.  The  sharp  forward  bend  of 
the  middle  band  is  characteristic  of  the  eastern  forms.  C.  formosa  is 
distributed  about  the  sand  dunes  of  Lakes  Michigan  and  Erie  and 
through  the  sand  areas  of  the  central  states,  the  distribution  being  very 
nearly  like  that  of  C.  sciitellaris  except  that  formosa  is  wanting  from 
Virginia  to  Texas  along  the  Atlantic  and  Gulf  Coasts. 

The  markings  of  the  western  Mississippi  basin  forms  are  broad  as 
shown  in  figure  531,  plat*  XXVIII,  while  m  the  more  southern  and 
western  forms  from  Texas,  Colorado,  and  Oklahoma  are  characterized 
by  a  middle  band  tending  to  be  straight  across  the  elytron. 

The  species  which  stands  close  to  this  is  C.  venusta  (Figs.  533  and 
534).  The  pattern  is  similar  to  that  of  C.  gencrosa.  It  occurs  only  in 
sand  areas  of  the  great  plains.  The  southern  repi'esentatives  have 
markings  similar  to  figure  531  in  width,  but  in  Manitoba  there  is  a 
tendency  to  the  extension  of  the  white  as  shown  in  figure  534.  G.  lim- 
hata  is  a  closely  related  species  which  is  taken  only  in  blowouts  in  sand 
hills  of  the  western  Nebraska  region  and  of  Manitoba.  Figures  535  and 
536  show  typical  patterns.     They  do  not  vary  greatly  geogi'aphically. 

C.  ancosisconensis  and  duodecemguttata  are  invariable  species  (Figs. 
528  and  529),  rcpanda  a  subspecies  of  12  guttata  distributed  almost 
everywhere  east  of  the  Rocky  mountains  in  the  United  States  and  Can- 
ada. Specimens  from  Louisana,  Manitoba,  and  Virginia  do  not  varj' 
appreciably.  The  lan'ae  inhabit  very  moist  soil  and  soil  temperature 
cannot  be  of  any  magnitude.  The  habitat  and  larval  habits  are  such 
that  variations  due  to  differences  in  temperature  and  moisture  are  not 
common.  If  the  soil  becomes  too  dry  the  larvae  leave  it  and  dig  a  new 
burrow  in  soil  of  the  wetness  required  by  the  species.  Since  they 
occur  near  water  courses,  this  tends  to  keep  larvae  in  similar  conditions 
no  matter  in  what  latitude  they  occur.  The  variation  of  oregona.  a 
related  species,  has  not  been  studied. 

C.  hirticollis  occurs  on  the  sandy  shores  of  the  sea,  lakes,  and 
rivers  from  Vera  Cruz  to  California,  the  Great  Lakes,  and  Massachu- 
setts. The  pattern  which  is  shown  in  figure  330,  plate  XVI,  is  quite 
invariable  as  compared  with  the  rest  of  the  species  considered.  High 
temperature  experiments  performed  with  these  showed  clearly  recogniz- 
able modification  in  which  the  pattern  duplicated  Southern  and  South- 
western forms.  The  experiments  and  geographic  and  otlier  variation 
are  likewise  parallel. 

C.  scxguitata  has  been  studied  and  shows  peculiar  variations.  Spec- 
imens from  the  Northeastern  United  States  and  the  region  of  the  Great 
Lakes  have  well  developed  markings  (Figs.  525  and  526,  PI.  XXVIII). 


46  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [440 

The  same  is  true  of  Texas  specimens.  Specimens  from  E.  Tennessee 
are  reduced  as  in  figure  523  and  those  from  eastern  Kansas  are  usually 
immaculate  with  a  few  like  523. 

C.  punctul<ita  representing  the  Mexican  group,  has  been  studied 
and  while  widely  distributed  fails  to  show  pattern  varieties  and  did  not 
show  any  modification  when  subjected  to  40°C  in  the  experiments.  It 
also  shows  no  geographic  variation  in  markings.  C.  lemniscata  shows 
the  vitta  broken  in  about  seventeen  out  of  seven  hundred  and  fifty 
individuals.  These  patterns  are  like  liitcolineata  (Fig.  24,  PL  III). 
C.  carthagena,  hacmorrhagica  and  C.  gahbi  of  San  Diego,  California, 
show  a  tendency  for  the  markings  to  disappear  by  the  spreading  of 
pigment  over  the  areas  of  the  markings. 

COLORS  OP  TIGER  BEETLES 

CAUSES    OF    COLORS 

The  pigment  present  in  the  cuticula  of  Cicindela  is  essentially  all 
in  the  primary  cuticula  (Fig.  1).  This  pigment  has  been  demonstrated 
by  Gortner  to  be  melanin  and  not  the  compounds  stated  by  Tower 
(1906).  This  pigment  is,  in  all  the  elytra  observed,  either  brown  or 
black.  It  is  the  result  of  the  oxidation  of  tyrosin  or  related  compound 
by  tyrosinase  (Riddle,  1909).  In  the  case  of  all  elytra  examined  in 
transmitted  light  which  covers  nearly  two  hundred  species  no  color  but 
dark  brown  ranging  to  black  has  been  observed,  no  matter  what  bril- 
liant spectrum  colors  were  present  in  the  elytra  as  view  in  reflected  light. 

Professor  Michelson  has  made  a  study  of  the  causes  of  the  bright 
metallic  and  spectrum  colors  in  various  insects  and  feathers  and  has 
found  that  the  colors  are  due  to  very  thin  surface  films,  metallic  in 
character.  He  has  very  kindly  examined  elytra  of  several  species,  in- 
cluding Cicindeki  chinensis  Dej.,  severaF  varieties  of  C.  limbalis,  and 
several  color  varieties  of  C.  scutellaris.  The  colors  of  the  first  two 
differ  in  different  parts  of  the  same  elytron,  the  second  named  species 
showing  blue  and  red  and  differing  sometimes  in  the  same  population 
from  black  to  green  or  blue,  red,  etc.  The  first  two  species  gave  results 
too  indefinite  to  report.  The  third  species,  C.  scutellaris,  occurs  on  the 
Atlantic  coast  as  a  brilliant  green  form  with  some  dead  black  forms 
among  them  in  the  same  population ;  and  in  Kansas  and  Oklahoma  the 
population  is  a  flame  red.  The  red  scutellaris  from  Kansas  showed  a 
"preponderance  of  red  in  the  spectrum,  negative  phase  change  at  red 
end  of  spectrum,  and  positive  phase  change  at  blue  end.  The  green, 
east-coast  forms  showed  excess  of  blue-green  with  positive  phase  change 
at  red  end  and  negative  phase  change  at  blue  end."  The  black  form 
which   occurs  as  a  part  of  the   general   population   with   the   green   is 


441]  COLORS  OF  TIGER  BEETLES—SHELFORD  47 

v.ithout  trace  of  color  and  acts  like  a  piece  of  black  paper.  They  are 
merely  without  the  filin  over  the  surface. 

Professor  Michelson  states  further  that  the  colors  are  chiefly 
if  not  entirely  true  surface  or  metallic  colors.  They  are  produced  by  a 
film  of  ultra  microscopic  thickness  probably  less  than  a  ten-thousandth 
of  a  millimeter.  He  is  inclined  to  attribute  differences  in  the  colors 
to  differences  in  the  chemical  constitution  of  the  film  and  color  changes 
during  ontogeny  to  changes  in  chemical  constitution,  but  states  that  this 
would  be  very  ditficult  to  demonstrate  on  account  of  the  minuteness  of 
the  film.  The  work  of  Heylaerts  (1870)  (see  page  48)  would  seem  to 
indicate  that  physical  conditions  or  differences  cause  a  change  or  differ- 
ence in  color  in  dried  specimens. 

Tower's  figure  copied  by  Folsom  must  be  incorrect  as  he  shows  such 
a  film  as  seen  under  the  microscope.  This  line  which  he  draws  appears 
as  a  dark  line  under  the  oil  immersion  lens;  it  is  probably  a  total  re- 
flection line  which  he  misinterpreted  under  the  influence  of  Professor 
Michelson  "s  verbal  statement,  that  surface  films  must  be  responsible  for 
brilliant  colors,  which  preceded  the  latter 's  investigation  by  several 
years. 

The  colors  of  the  group  which  are  on  the  whole  exceptionally  brill- 
iant are  to  be  attributed  to  a  brown  or  black  pigment  either  without  or 
with  any  film  or  with  films  of  varying  effectiveness  and  with  varying 
effects  on  the  light  reflected  from  the  surface.  A  change  in  color  with 
a  change  in  the  angle  of  incidence  indicates  the  presence  of  metallic 
film. 

ONTOGENY  OP  COLOR 

One  of  the  striking  phenomena  in  connection  with  the  study  of  the 
ontogeny  of  patterns  is  the  ontogeny  of  color  as  opposed  to  pigment. 
Plates  XXIX,  XXX,  and  XXXI  are  devoted  to  this  subject  and  show 
a  series  of  radical  changes  in  the  character  of  the  coloration  associated 
with  stages  of  development.  Plate  XXIX  is  devoted  to  the  ontogeny 
of  color  in  C.  scutellaris  lecontci.  Figure  543  shows  the  beginning  of 
color  on  the  ventral  side  which  consists  of  bluish  reflections,  at  first 
about  the  center  of  segments  which  later  become  green.  Later  figure 
541  shows  purple  reflections  at  points  which  remain  so  throughout  with- 
out change,  showing  that  changes  do  not  always  take  place.  The  tip 
of  the  abdomen  and  trochanters  appears  not  to  have  a  surface  film. 

Considering  the  colors  of  the  dorsal  side  and  elytra  we  note  that 
at  the  beginning  the  color  is  a  yellow,  the  usual  color  of  the  cuticula 
when  backed  up  by  the  tissues,  with  greenish  reflections.  After  a  little 
time  green  color  begins  to  appear  more  prominent  and  the  elytron  of 


48  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [442 

this  normally  brown  species  resembles  the  green  form  of  the  Atlantic 
coast  (Fig.  553),  differing  only  in  lacking  bluish  reflection.  From  3 
to  15  days  yellow  reflections  are  at  their  maximum.  Specimens  occas- 
ionally are  collected  in  this  stage  (September).  After  this  the  color 
begins  to  sliift  to  red  or  dull  brownish  red,  but  has  still  greenish  reflect- 
ions in  some  individuals  which  gradually  disappear  with  hibernation. 
The  reddish  reflections  lo6se  luster  and  turn  to  a  dull  brown  by  the  time 
the  adult  dies  in  the  latter  part  of  June  after  reproducing  (Fig.  551). 
Important  differences  occur  between  individuals  collected  at  dift'erent 
times  of  year. 

Figures  559  to  562,  plate  XXX,  show  the  development  of  the  color 
in  C.  hirticollis.  Here  again  the  color  begins  as  green  and  gradually 
shifts  to  brown  or  reddish  brown.  There  are  no  green  varieties  of  this 
species  but  it  often  shows  greenish  reflections  in  the  adult  condition. 
This  is  more  pronounced  in  fresh  individuals. 

Figures  563  to  565  show  the  development  of  the  color  in  C.  pur- 
piirea;  the  first  stage  shown  (Fig.  563)  compares  favorably  with  some 
forms  of  the  variety  graminea.  As  time  goes  on  the  color  shifts  to  red 
over  the  upper  surface  of  the  elytron  and  the  blue  margin  shifts  to 
green,  both  shifts  being  down  the  spectrum.  Black  specimens  occur 
with  this  species  in  the  localit.y  where  the  larval  stages  were  collected 
for  these  observations. 

C.  purpurea  limhalis  shows  a  similar  series  of  stages,  and  the  sliift- 
ings  which  are  similar  to  those  in  the  form  purpurea-graminea-audu'boni 
shown  above.  In  general  during  ontogeny  in  the  species  noted  the  color 
shifts  dovn\  the  spectrum  as  the  cuticula  hardens  and  pigment  appears. 
In  fact  from  blue  to  green  the  change  is  direct;  but  in  ])assing  from 
green  to  red  the  orange  and  yellow  are  not  noticeable  or  at  most  occur 
as  slight  reflections;  green  changes  to  reddish  green,  red,  and 
finally  a  dingy  brown  almost  black  in  a  few  individuals  collected  in 
August  and  September  with  the  new  generation.  A  series  of  individ- 
uals killed,  pinned,  and  dried  so  as  to  show  a  series  from  the  beginning 
of  color  development  to  completion,  is  remarkable  in  that  the  earliest 
stage  when  dried  is  dull  black,  the  second  purple,  the  third  blue,  and 
individuals  in  the  green  stage  (Fig.  573,  PI.  XXXI)  usually  turn 
fiery  red  on  drying  (Fig.  576,  PL  XXXI).  Heylaerts  (18701  performed 
experiments  on  color  changes  in  some  European  species.  Brown  speci- 
mens of  C.  hyhrida  when  heated  to  102°C.  turn  green  and  remain  so 
for  a  short  time  when  exposed  to  the  atmosphere.  The  change  to  brown 
is  hastened  bj^  blowing  the  breath  on  them.  They  remain  green  in  a 
sulphuric  acid  desiccator.  Green  C.  campestris  turn  blue  when  simi- 
larly treated.     These  changes  accompany  the  almost  complete  removal 


443]  COLORS  OF  TIGER  BEETLES— SHELFORD  49 

of  moisture  from  the  surface  film  and  are  in  the  opposite  direction  as 
compared  with  the  ontogeny  changes  and  the  changes  which  take  place 
on  drying  of  fresh  immature  specimens.  The  cause  of  these  physical 
changes  is  unknown.  Other  shiftings  in  color  have  been  noted;  one 
of  these  in  C.  lepida  is  of  particular  interest  as  the  change  is  in  the 
direction  opposite  to  that  already  noted.  C.  lepida.  has  the  elytron 
nearly  all  white  but  such  parts  as  are  pigmented  are  green  in  the 
adult.  When  the  pigment  begins  to  develop  it  is  a  brilliant  gold  and 
remains  so  for  several  days,  finally  changing  to  a  dark  green.  In  this 
case  the  change  is  the  only  one  of  the  kind  noted.  Golden  yellow 
blending  with  green  is  commonest  in  cuprascens  sperata,  circumpicta, 
and  related  species.  These  may  shift  from  green  to  brown  through 
yellow  instead  of  red  but  their  ontogeny  has  not  been  studied. 

Even  the  dull  species  like  C.  12 ^guttata,  and  repanda,  and  occa- 
sionally C.  punciulaia  show  more  green  in  the  early  stages  and  turn 
brown  as  they  mature.  The  early  stages  of  C.  tranquebarica  are  black- 
ish green,  graduallj-  turning  bronze  brown  as  more  pigment  is  devel- 
oped. C.  formosa  is  at  first  reddish  and  gradually  changes  to  brown ; 
some  individuals  collected  in  the  autumn  are  red. 

RELATION  OP  ONTOGENETIC   STAGES   TO  GEOGRAPHIC  RACES 

First  of  all  it  should  be  noted  that  there  appears  to  be  no  good 
reason  for  assuming  that  the  biogentic  law  holds  good  with  reference 
to  these  color  changes;  it  would  be  only  the  most  radical  adherent  who 
could  see  it  applying.  However  in  a  general  way  the  developmental 
stages  of  a  given  species,  like  C.  scutellaris  lecontei,  may  practically 
reproduce  the  color  of  another  variety  in  ontogeny.  Compare  figure 
546  with  figure  553,  plate  XXIX.  The  stages  in  the  development  of 
typical  C.  purpurea  do  quite  exactly  duplicate  some  of  the  races  rec- 
ognized. Tlius  the  stage  shown  in  Figure  563  practically  duplicates 
the  color  of  graminea  while  Figure  564  duplicates  some  of  the  speci- 
mens of  the  subspecies  10  notatta.^ 

Again  in  Figure  572  appears  an  ontogeny  stage  which  resembles 
very  closely  the  variety  denverensis  but  is  less  yellowish;  denverensis 
also  usually  lacks  the  blue  green  margins,  though  the  green  is  purer 
and  brighter  along  the  margin,  showing  a  difference  comparable  to 
that  seen  in  nearly  aU  specimens  of  purpurea. 

C.  hiriicollis  shows  a  stage  in  the  development  of  color  (Figs. 
559  to  562,  PI.  XXX)  which  corresponds  very  closely  to  the  race  of  the 
species  occurring  on  the  Pacific  Coast.  In  addition  to  this  it  shows 
slight  Inflections  of  the  bluish  of  the  bluish  drab  forms  of  Vera  Cruz. 
Reddish  brown  forms  occur  in  southwestern  Kansas. 

Occasional  specimens  of  C.   tranejucbarica  collected  in  Massachu- 


50 


ILLINOIS  BIOLOGICAL  MOXOGRAPHS 


setts,  show  the  dull  green  occurring  in  ontogeny.  Similar  greenish 
reflections  occur  in  the  western  forms,  but  this  blends  with  dark  color 
instead  of  brown. 

The  light  wine  color  of  the  high  altitude  form  of  C.  formosa 
(Salida,  Colorado,  7000  ft.)  is  duplicated  in  the  ontogeny  of  color  in 
C.  formosa  from  near  Chicago.  Specimens  which  have  this  color  are 
sometimes  collected  in  the  late  summer  near  Chicago,  but  none  have 
been  taken  in  the  spring. 

C.  pimctulata  appears  not  to  possess  a  film  such  as  described,  as  a 
rule,  and  the  changes  during  ontogeny  are  not  marked.  The  brilliant 
green  forms  which  occiir  in  the  southwest  have  no  counterpart  in 
ontogeny. 

Nearly  all  the  species  of  the  tranquebarica  group,  as  well  as  many 
others,  show  a  great  series  of  colors.  The  following  shown  in  Table  II 
occur : 


Showing 

Colors   0 

Table  II 
"curring  in   Several 

North   American   Species 

5 

c 

5 

o 

1 

•o 

5 

O 

■o 
c 

5 

3 

5 

-3 

c 

5 

"3 

> 

n 

o 

X 

X 

X 
X 

X 

X 

X 

X 
X 

z 

X 
X 
X 

X 

X 
X 

X 

X** 

X 

X 
X 

X* 
X 

X 

> 
> 

> 

X 

X 

X 

X 

X 
X 
X 

X 
X 
X 

x 

X 

X 

X 
X 

X 
X 

X 

X 

X 
X 
X 
X 

X 

X*** 

X 
X 

* 

tranquebarica    

nigrocoerulea 

oregona     

formosa    

hirticollis    

repanda    

willistoni  

fulgida  

pulchra    

X 

anthracina    

X 

X 

X 
X 

X 
X 
X 
< 

X 
X 

X 

X 

X 

X 
X  < 

cuprascens 

lepida 

X 

*Reflections  in  western   forms. 
**Reddish  brown. 
***Dull  bluish  drab.     Vera  Cruz,  Me.xico. 

In  scutellaris,  purpurea,  anthracina,  and  sexguttaia  black  and 
green  forms  are  mixed,  i.e.,  the  species  are  dimorphic.  The  same  is 
probably  true  of  tranqueharka,  as  plutonica  appears  to  be  rare  and 


445]  COLORS  OF  TIGER  BEETLES— SHELFORD  51 

occurs  in  California  where  the  usual  population  is  green.  The  physio- 
logical condition  in  which  no  metallic  film  is  secreted  is  closely  related 
to  one  in  which  a  metallic  film  producing  green  is  secreted. 

The  secretion  of  a  film  which  lies  at  the  outside  of  the  primary 
cuticula  in  the  first  work  of  the  hypodermal  cells.  It  would  seem 
that  the  secretion  of  such  a  layer  might  be  inhibited  by  environic 
stimuli!  at  a  critical  stage  in  the  life  of  the  pupa,  but  there  appears  to 
be  no  experimental  results  showing  whether  or  not  this  is  true.  If 
environmental  conditions  do  influence  the  occurrence  of  black  and  green, 
climatic  conditions  applicable  to  all  species  are  not  alike  (see  p.  52). 

In  the  case  of  C.  scutellaris  the  green  and  black  forms  have  least 
pigment  developed  in  the  elytra  (black  is  accompanied  by  a  similar 
amount),  and  green  in  ontogeny  is  accompanied  by  least.  The  amount 
increases  as  the  reddish  color  comes  in,  in  lecantei.  The  amount  of 
pigment  in  the  brilliant  red  western  form  is  intermediate  between  the 
green  form  and  the  dark  red  lecontei.  C.  splendida,  very  brilliant,  shows 
much  less  pigment  than  limbalis,  which  is  dull. 

Many  species,  particularly  purpurea  and  pulchra,  show  more  bril- 
liant colors  along  the  elytra  margin  where  white  markings  usually 
occur.  This  is  noticeably  true  in  purpurea,  which  in  the  subspecies 
cimarrona  has  a  complete  white  margin  in  many  specimens.  As  a  rule 
when  the  areas  commonly  occupied  by  markings  become  pigmented  the 
colors  in  these  areas  are  more  brilliant.  W.  Horn  (1915)  has  called 
attention  to  this.  As  has  been  noted,  the  elytral  surface  of  most  tiger 
beetles  is  made  up  of  small  hexagonal  pits  which  jirobably  convspond 
to  the  hypodermal  cells  which  secreted  it  (Fig.  1,  PI.  I).  The  ridges 
between  these  lie  over  the  boundaries  of  the  cells.  In  the  elytra  of 
C.  purpurea  these  pits  are  smaller  in  the  blue-green  margin.  The  same 
is  true  of  many  other  species  as  shown  in  Table  III. 

Wliile  many  colors  such  as  green  and  greenish  blue,  red,  etc.,  in 
early  ontogeny  change  to  colors  of  longer  wave  length  during  ontogeny 
and  later  life,  such  is  not  true  during  ontogeny  at  least  in  the  case  of 
such  purple  specimens  of  C  scutellaris.  These  are  rare  and  only  a 
fe\v  specimens  from  Starved  Kock  (Utica),  Illinois,  have  been  found; 
.some  of  these  are  purplish  brown,  but  one  individual  was  secured  in  the 
larval  stage  and  reared  (Fig.  558,  PI.  XXIX).  It  was  purple  from 
the  beginning  and,  never  showed  any  tendency  to  change,  though  it 
was  kept  for  a  long  time.  The  same  is  probably  true  of  the  purple 
forms  of  C.  sexguttata  which  occur  in  eastern  Kansas;  purple  forms 
of  nigrocoerulea  show  no  blends  with  the  green. 


tJ?  I 


52 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[446 


Table  III 
The    following   table   shows   the   relative   size   of   hexagonal   cups    in   various 
forms  and  parts  of  the  same  elytron,  etc. 


Species 


Variety 


Locality 


Organ 


Part 


Color 


Diameter 
in  mm. 


C.  purpurea.. 


"  scutellaris.. 


"   generosa.. 


chinensis.. 


deni)erensis. 
lecontei  


scutellaris 

rugifrons 
modesta  ■— 


Massachusetts...  elytron 
Chicago 


Penver  . 
Chicago.. 


Colorado 


China 


margm 
disc 

margin 
disc 


disc 


green., 
red 

green.. 


brown.. 
f  red 

i    "  


[  green., 
green., 
black.. 
red 


\  blue 
[  metallic 


0.0115 

0.0150 

0.0115 

0.015 

0.0150 

0.0150 

0.013 

0.0115 

o.oioo 

0.0 1 00 

0.0150 
f  0.015    to 
]  0.0225 
[  0.018  av. 

0.013 


GEOGRAPHIC    VAEIATION   IN    COLOR 

The  black  forms  of  C.  scutellaris  are  found  to  occur  in  some 
New  York  localities,  and  some  New  England  localities,  but  are 
less  numerous  than  green  ones.  A  complete  catch  from  Providence, 
Ehode  Island,  for  one  season,  including  hibernated  and  freshly 
emerged  forms,  showed  less  than  20  per  cent  black  individuals ; 
a  similar  catch  from  Framingham,  Massachusetts,  gave  no  black 
individuals;  112  specimens  from  Aqueduct,  New  York,  showed 
about  15  per  cent  black.  Some  localities  in  New  Jersey  show, 
according  to  Leng,  a  majority  of  black  forms  in  spring,  A  small 
catch  from  Baltimore,  Maryland,  showed  more  than  half  black  forms. 
At  Raleigh,  North  Carolina,  black  forms  do  not  occur,  and  I  find  no 
records  for  Virginia,  North  Carolina,  and  South  Carolina ;  but  black 
forms  occur  in  Alabama,  Georgia,  and  Florida.  At  Mobile  a  few  black 
ones  are  found  in  the  autumn  but  very  few  or  none  at  all  in  the  spring, 
according  to  Messrs.  Loding  and  Van  AUer  who  have  been  interested  in 
them  for  several  years.    None  are  recorded  for  points  farther  west. 

Black  forms  of  C.  sexguttata  likewise  occur  in  the  eastern  states. 
New  Jersey  and  Pennsylvania,  but  not  in  the  southern  localities.  Black 
forms  of  C.  purpurea    (see    map,    Fig.    472)    occur    in    Illinois,    Iowa 


447]  COLORS  OF  TIGER  BEETLES— SIIELFORD  53 

Minnesota,  Kansas,  Nebraska,  South  Dakota,  Colorado,  Utah,  Wyom- 
ing, and  New  ilesico,  but  are  very  rare  in  eastern  localities.  Mr. 
C.  A.  Frost  secured  one  bluish  black  individual  in  Massachusetts.  The 
black  forms  of  C.  tranquebarica  are  recorded  from  a  single  locality 
in  California.  No  black  forms  occur  in  the  localities  where  black 
forms  of  other  species  occur  though  blackish  green  forms  occur  in  the 
Pacific  States  and  blackish  brown,  in  the  Gulf  States.  Likewise  there  is 
no  correlation  between  geographic  conditions  and  green  forms.  Scutel- 
laris  is  green  on  the  Atlantic  coast,  purpurea  in  the  central  and  north- 
ern great  plains,  tranquebarica  on  the  coasts  and  coastal  mountains. 

Exclusive  of  black  forms  which  have  just  been  discussed  the  geo- 
graphic variation  of  colors  in  the  species  belonging  to  the  tranquebarica 
group,  may  be  stated  as  follows:  Geographic  variations  in  color  are 
of  special  interest  in  the  case  of  C.  scutcllaris;  I  note  green  forms  pre- 
dominating in  all  specimens  in  the  Atlantic  Coast  and  Gulf  States. 
Bluish  retlections  characterize  these  as  a  rule,  particularly  in  some 
localities  where  occasional  blue  forms  occur  (Fig.  470  a). 

In  Texas  along  the  northeastern  border  near  Oklahoma  forms 
occur  with  a  decided  golden  cast  which  in  series  in  some  localities  range 
from  bluish  green  through  green  with  golden  cast  to  flame  red  like 
figure  554,  plate  XXIX ;  north  of  this  flame  red  predominates.  Forms 
with  flame  red  eh'tra  and  green  or  blue  thorax  occur  west  to  the  Rio 
Grande,  occupying  a  triangular  area  with  its  apex  just  north  of  the 
Black  Hills  and  eastern  point  near  Topeka,  Kansas.  Points  a  short 
distance  west  of  the  Missouri  River  such  as  Topeka,  Kansas,  and  Su- 
perior, Nebraska,  show  great  variation  in  marking  and  all  intermedi- 
ate color  conditions  between  the  forms  with  flame  red  elytra  and  those 
of  tlie  dull  brown  and  wine  color  occurring  to  the  east  and  north  of 
the  ilissouri  River.  The  most  brilliant  wine  colors  occur  between  the 
Mississippi  and  Jlissouri  Rivers  and  in  Manitoba;  near  Chicago 
the  brilliant  wine  colors  are  not  usual,  but  greenish  browns  and  green- 
ish individuals  are  common.  There  appears  to  be  no  close  correlation 
between  the  distribution  of  these  colors  and  any  mapped  distribution 
of  factors. 

C.  purpurea  is  very  variable ;  figures  471  a,  472  show  color  varie- 
ties of  this  species.  In  general  among  the  groups  in  which  tlic  mark- 
ings are  withdrawn  from  the  margin,  the  forms  with  the  n[)per  part 
of  the  elytron  reddish  and  its  margins  green  are  most  widely  distrib- 
uted, extending  almost  throughout  the  range  of  the  species  except  the 
Pacific  coast  specimens  which  are  golden  green  (Puget  Sound,  10  ft.).  / 
The  eastern  forms  are  of  the  typical  red  elytroned  type.  In  the  entire  "/ 
^Mississippi  Basin,  Great  Plains,  and  Salt  Lake  Valley  tliis  is  mixed 
with  green  and  black  fonns,  the  latter  two  predominating  in  the  west- 


J. 


54  ILLfXOIS  BIOLOGICAL  MONOGRAPHS  [448 

ern  Great  Plains.  In  the  New  Mexico  localities  dark  brown  forms 
(ciniarrona)  occur.  There  is  no  correlation  between  color  and  mapped 
climatic  conditions  unless  it  be  rainfall. 

Considering  the  purpureas  in  which  the  reduction  of  markings 
leaves  only  a  small  dash  at  the  margin  of  the  elytron,  one  notes  that 
the  wine  colored  specimens  are  distributed  throughout  the  region,  of 
the  Great  Lakes  and  in  Manitoba  and  generally  westward  to  the  Mis- 
souri River,  .and  Colorado.  This  type  is  distributed  in  a  general  way 
north  of  about  41  degrees  North  Latitude  and  has  the  thorax  the  same 
color  as  the  elytron.  The  forms  splendida  and  transversa  are  similar 
in  color  but  have  the  thorax  green  or  blue  and  the  elytron  either  red 
or  wine  color,  they  are  distributed  south  of  the  form  with  red  thorax 
and  in  the  eastern  part  of  the  range  ai-e  less  brilliant  than  farther 
west.  The  more  western  forms  have  brilliant  red  elytra  similar  in 
color  to  that  of  the  red  scutellaris.  Mixed  with  these  are  the  green 
forms;  in  western  Kansas  and  Colorado,  especially,  they  occur  with  the 
red  forms  and  are  often  taken  in  coitus  with  them.  The  green  form 
is  evidently  merely  a  color  aberration  of  the  red  form. 

The  color  variation  of  C.  tranqueharica  is  not  striking  over  the 
entire  area  east  of  the  Rockies.  Nearly  all  are  simply  dull  brown. 
Specimens  from  the  moist  southern  states  are  usually  duller  blackish 
brown  than  the  northern  forms.  No  striking  color  varieties  occur  even 
east  of  the  Pacific  states  and  Idaho.  In  some  parts  of  eastern  Califor- 
nia (Bridgeport)  they  are  brown,  while  only  a  little  waj^west  they 
are  green ;  further  surprising  differences  were  found  in  Nevada.  At 
Caliente  the  writer  took  brown  tranqueharica  and  blue  oregona,  while 
nt  Las  Vegas  he  took  green  and  bluish  tranqueharica  and  no  oregona, 
^ .  hich  occur  there  and  are  probably  green  also,  but  there  is  no  apparent 
reason  why  oregona  should  be  blue  or  green  and  tranqueharica  brown 
in  a  region  where  both  are  likely  to  be  green. 

C.  generosa  is  brown  and  wine  color  in  eastern  localities  and 
where  purpurea  is  similarly  colored.  Near  Chicago  the  colors  are  simi- 
lar. At  Topeka,  Kansas,  the  color  varies  considerably,  reddish,  bluish, 
and  greenish  brown  occur.  South,  and  sotithwest  from  this  point  the 
specimens  are  progressively  redder.  The  most  brilliant  forms  are  the 
red  ones  from  western  Oklahoma,  western  Texas,  and  Colorado.  At 
low  altitudes  these  are  golden  red.  Wine  red  occurs  at  high  altitude 
(Salida,  Colorado,  7,000  ft.).  C.  hirtieoUis  has  already  been  discussed 
(see  page  49).  With  the  exception  noted  there  is  little  variation  and 
distribution  is  transcontinental  and  from  the  Great  Lakes  to  Vera  Cruz. 


449]  COLORS  OF  TIGER  BEETLES— SHELFORD  55 

EXPERIMENTAL    MODIFICATION    OF    COLOR 

This  is  froiight  by  many  difficulties  on  account  of  the  remarkable 
series  of  colors  and  color  changes  occurring  in  ontogeny,  and  the  usual 
early  death  of  individuals  reared  under  experimental  conditions.  Fig- 
ure 555,  plate  XXIX,  shows  an  experimentally  modified  individual 
of  C.  lecotitei.  The  presence  of  the  yellowish  color  in  the  markings 
indicates  that  secondary  cuticula  has  been  secreted  with  the  air  spaces 
between,  in  quantity  sufficient  to  give  the  opaque  appearance  to  the 
markings.  This  specimen  in  particular  was  known  to  have  died  15 
days  after  it  was  dug  out  of  the  soil,  which  is  not  until  the  cuticula 
is  well  hardened.  Its  markings  are  reduced  below  anything  ever 
found  near  Chicago.  The  color  shows  an  unusual  amount  of  yellow 
and  approaches  most  nearly  to  some  of  the  western  forms  of  scutcllaris 
(Fig.  554)  though  not  exactly  like  any  forms  known  to  occur.  This 
particular  individual  showed  more  yellow  and  was  most  generally  modi- 
fied, leaving  no  doubt  as  to  the  fact  that  color  modification  had  oc- 
curred. Three  other  individuals,  all  of  wliich  lived  long  enough  to 
show  the  development  of  opaqueness  in  the  wliite  markings,  were  pro- 
duced and  showed  green  of  unusual  clearness  from  reddish  brown 
and  suggestive  of  green  forms  rather  than  the  parent  stock  of  Iccontei. 
All  these  were  in  dry  conditions.  The  warm  moist  experiments  show-ed 
green  forms  but  not  clearly  differentiated  from  ontogeny  stages  in  part 
due  to  earl}'  death. 

Three  specimens  (Fig.  557)  were  brought  through  successfully  in 
icing  experiments  and  lived  two  weeks  or  more.  Two  of  these  were 
characterized  by  broad  markings  and  dull  brown  elytra  and  rather 
striking  differences  between  the  color  of  the  head  and  the  thorax,  the 
latter  being  quite  green.  Figure  557  shows  considerable  modification 
of  form  and  size  not  noted  in  the  other  two.  The  very  rounded  ends 
of  the  elytra,  and  square  shouldered  character  was  quite  striking  and 
in  direct  opposition  to  the  usual  tendency  sliown  in  the  rest  of  the 
group. 

Figure  556  shows  a  specimen  brought  tlirougli  at  37°C.  with 
raarked  acceleration  of  development.  This  individual  was  small,  slen- 
der in  the  head  and  thoracic  region,  with  the  el.ytron  widest  in  the 
region  behind  the  middle  band.  The  color  is  much  brighter  and  freer 
from  dull  brown  reflections  than  that  of  the  normal  specimens,  having 
a  decided  brilliancy  to  the  color.  This  specimen  was  kept  alive  until 
the  opaque  appearance  of  the  markings  was  well  developed.  This  body 
form  is  characteristic  of  many  specimens  from  the  extreme  southern 
states.  There  is  a  noticeable  general  tendency  toward  this  general 
body  form  in  all  individuals  reared  in  high  temperature. 


56  ILLIXOIS  BIOLOGICAL  MOXOGRAPHS  [450 

Experiments  were  performed  on  C.  hirticollis  which  paralleled 
those  noted  on  C.  scutellaris,  but  with  results  on  markings  and  none 
so  far  as  color  is  concerned.  It  is  probable  that  the  experimental  indi- 
viduals showed  more  green  than  others,  but  the  difference  is  too  slight 
to  justify  an  unqualified  statement  to  that  effect.  One  striking  result 
was  obtained  in  the  experiments  where  the  temperature  of  about  37°C. 
was  maintained  on  larvae  which  had  not  hibernated;  one  small  indi- 
vidual was  obtained  (Fig.  566)  which  however  retained  all  the  striking 
characteristics  of  the  species. 

Experiments  on  C.  tranqucharica  were  successful.  Specimens 
reared  in  temperature  of  37°C.  and  much  moisture  (Fig.  570)  showed 
the  dull  blackish  brown  which  characterizes  the  colors  of  some  of  the 
specimens  from  the  moist  southern  states.  This  color  was  not  iiniform 
throughout  the  series  so  raised,  but  was  much  commoner  than  in  the 
ease  of  specimens  reared  in  hot  dry  conditions,  as  these  are  more  bril- 
liant (Fig.  569).  A  number  of  specimens  were  iced  but  only  one  of 
these  was  especially  peeiiliar  (Fig.  568).  This  was  decidedly  more 
red  than  any  others  seen  in  the  course  of  my  studies.  Some  of  the 
iced  specimens  were  unusually  dull,  however,  and  no  uniform  results 
were  noted  except  that  the  heads  were  uniformly  greener. 

C.  limhalis  was  subjected  to  high  temperature.  In  the  moist  con- 
ditions dull  colors  were  obtained.  Figure  577  shows  one  of  the  high 
temperature  individuals  in  which  the  color  is  deeper  red  and  the  re- 
flections more  striking  blue  than  in  the  normal  specimen  at  this  stage 
(Fig.  575).  579  which  shows  an  individiial  subject  to  high  temper- 
ature in  moist  conditions  is  morei  generally  dull  green.  578  shows 
an  iced  specimen  which  is  similar  to  the  warm  moist  individual. 
These  differences  are  slight  and  not  very  convincing,  but  the  individ- 
uals are  different  from  any  reared  or  collected  under  other  conditions. 

Experiments  of  a  similar  character  were  performed  on  C.  punc- 
tulata  but  appeared  to  be  without  results.  A  similar  series  on  C.  lepida 
were  likewise  witliout  results. 

RELATION  OP  COLORS  AND  COLOR  PATTERNS  TO  CLIMATE 

After  a  thorough  study  of  the  subject  and  comparison  of  the  dis- 
tribiitiou  maps  of  several  species  with  maps  showing  the  rate  of  evapo- 
ration of  water  for  the  year,  the  evaporation  of  water  from  the  porous 
cup  atmometer  from  April  to  September,  the  ratio  of  rainfall  to  evapo- 
ration, mean  annual  temperatiire,  temperature  April  to  September, 
and  with  maps  showing  cloudiness,  humidity,  rainfall,  etc.,  it 
was  demonstrated  that  the  distribution  of  color  varieties, 
and  pattern  varieties  even  where  the  types  are  quite 
distinct,  is  not  correlated  with  the  conditions  shown  on   such  maps. 


451]  COLORS  OF  TIGER  BEETLES— SHELFORD  57 

111  general  such  correlation  is  closest  in  relation  to  rainfall,  but  this 
correlation  is  not  so  good  as  one  would  expect  (Fig.  470  a,  PI.  XXIV). 
This  is  perhaps  to  be  expected  in  the  ease  of  species  which  belong  to 
local  conditions  which  is  true  of  most  of  the  species  of  Cicindela.  This 
subject  has  been  discussed  in  some  detail  ( Shelf ord,  1911).  Here  it 
was  shown  that  species  which  were  distributed  in  a  major  climatic 
habitat  had  a  distribution  correlated  with  the  distribution  of  vegeta- 
tion, which  in  turn  is  correlated  with  the  distribution  of  climatic  con- 
ditions. I  showed  further  that  species  such  as  C.  tranqucharica  trav- 
ersed almost  the  entire  continent  without  much  variation  by  virtue  of 
living  in  moist  soil,  due  either  to  climatic  moisture  or  to  local  stream 
moisture  or  lake-shore  moisture.  C.  scutcllaris,  C.  purpurea  and  most 
of  the  other  species  noted  are  found  in  some  special  kind  of  soil  such 
as  sand  containing  a  little  humus  (Shelford,  1911,  1913b)  or  steep  clay- 
banks  or  some  other  restricted  situation.  Taking  C.  scutellaris  for 
example,  this  species  being  found  in  well  drained  or  dry  sand  contain- 
ing a  little  humus  and  bound  by  scattered  vegetation  throughout  its 
range,  it  is  to  be  expected  that  the  distribution  of  the  species  will  be 
correlated  with  some  sort  of  measured  soil  conditions  such  as  soil  tem- 
perature, soil  wilting  coefficient,  or  the  like ;  but  no  such  conditions 
have  been  recorded  or  mapped.  There  is  some  evidence  of  soil  effects 
in  this  species  (see  Fig.  558,  PL  XXIX).  Some  specimens  from  the 
verj'  coarse  sands  resiilting  from  the  weathering  of  St.  Peter's  sand 
stone,  near  Utica  (Starved  Rock),  Illinois,  are  purple.  No  purple 
forms  have  been  taken  elsewhere.  Two  specimens  from  sandy  clay 
(Suman,  Indiana)  had  an  unusual  silky  appearance.  When  soil  tem- 
perature work  under  way  is  published,  I  shall  attempt  to  make  use  of 
the  extensive  records  which  have  been  accumulated  for  the  purpose  of 
working  out  correlation  between  conditions  and  color  and  pattern  va- 
rieties. Conditions  associated  with  altitude  influence  color  in  some 
cases,  but  there  is  no  unity  of  conditions  or  colors. 

GEOGBitPHlC   CENTER  OP  THE  GROUP  ON  THE  BASIS  OP  PATTERNS 

The  usual  criteria  for  the  center  of  distribution  (Adams,  1902) 
indicate  that  the  Oriental  region  or  at  most  the  Oriental  and  Ethio- 
pian regions  (shores  of  the  Indian  Ocean)  are  the  geographic  center 
or  center  of  distribution  of  the  group.  The  first  evidence  presented 
which  indicates  this  is  found  in  table  I,  in  which  eleven  groups  of 
species  are  shown  to  occur  in  the  Oriental  region  and  in  other  regions, 
while  not  more  than  six  occur  in  any  one  other  region  and  at  the  same 
time  in  still  others. 

Patterns  are  divisible  into  three  great  gro\ips:  first  those  without 
the  spots  at  the  base  and  along  the  inner  border  of  the  elytron  shown 
to  the  left  of  the  bottom  of  figure  580;  these  patterns  represent  the 


58  ILLIXOIS  BIOLOGICAL  MOKOCRAPHS  [452 

usual  tyj)e  of  the  group  aud  are  world  wide  in  distribution.  The 
patterns  to  the  right  of  these  are  those  with  the  basal  spot  and  the 
two  spots  along  the  inner  border,  shown  on  the  map  by  the  stippled 
area ;  this  includes  a  number  of  pilosity  groups  and  thus  represents 
considerable  diversity.  The  group  in  which  the  middle  cross  band  (4) 
is  oblique  in  the  reverse  direction  as  compared  with  that  which  is  usual 
in  the  group  as  a  whole,  is  shown  by  small  circles.  This  is  essentially 
confined  to  the  Oriental  region.  There  are  a  few  species  in  Africa 
which  show  this  and  which  appear  somewhat  related  on  the  basis  of 
pilosity,  but  circles  are  omitted.  The  group  of  species  and  patterns 
shown  at  the  extreme  right  and  represented  on  the  map  by  the  short 
oblique  lines  constitute  a  group  divided  between  the  Oriental  and 
Ai;stralian  regions. 

An  over-lapping  of  the  various  t\T3es  in  the  Oriental  region  is  evi- 
dent. This  would  place  the  center  for  the  group  in  that  region  but 
several  African  species  appear  to  be  most  primitive  from  the  standpoint 
of  kind  of  patterns  shown.  It  accordingly  seems  best  to  consider  that 
the  lands  adjoining  the  Indian  Ocean  constitute  the  center  of  distri- 
bution of  the  group. 

GENERAL   DISCUSSION 

The  evidence  which  must  support  any  conclusions  drawn  is  of 
such  a  character  and  drawn  from  so  many  sources  that  the  presentation 
of  a  few  lines  of  evidence  and  the  conclusions  forthcoming  from  them 
can  best  follow  the  general  presentation  of  data  and  minor  conclusions 
on  the  preceding  pages.  Since  color  and  color  pattern  are  quite  dis- 
tinct so  far  as  laws  governing  them  are  concerned,  the  discussion  of 
the  two  will  be  separated. 

PATTERN    TENDENCIES 

Under  this  head  we  are  concerned  with  (a)  the  original  type,  (b) 
the  most  characteristic  elements  and  combination  of  original  charac- 
ters, (c)  general  laws  of  pattern  modification  applicable  to  groups  of 
species,  (d)  laws  applicable  to  particular  species,  and  (e)  laws  appli- 
cable to  subdivisions  of  species. 

As  has  been  noted  the  number  of  directions  in  which  modification 
has  preceded  are  numerous  and  any  statement  of  siich  directions  is 
difficult  aud  has  led  other  authors  to  make  general  statements  regarding 
the  modification  of  patterns  which  were  general  enough  to  apply  to  a 
large  number  of  species. 

The  earliest  account  of  variation  in  the  color,  or  markings  or  the 
patterns  of  tiger  beetles  is  that  of  Dr.  Geo.  H.  Horn  (1892).    He  took 


453]  COLORS  OF  TIGER  BEETLES— SHELFORD  59 

the  marking  of  C.  tranquebarica  Herbst  as  the  underlying  type  "from 
which  all  forms  observed  in  our  Cicindelas  have  been  derived".  He 
bases  this  statement  on  the  fact  that  it  is  the  so-called  humeral  lunule, 
middle  baud,  aud  apical  lunule  which  give  similarity  to  the  patterns 
of  the  genus.  He  states  that  modification  occurs  in  any  one  of  four 
ways : 

A.  By  progressive  spreading  of  the  white. 

B.  By  gradual  thinning  or  absorption  of  the  white. 

C.  By  fragmentation  of  the  markings. 

D.  By  linear  supplementary  extension  of  the  white. 

These  tendencies  are  all  recognizable,  all  of  them  occurring  in  the 
course  of  individual  and  geographic  variation  of  single  variable  species. 

Walther  Horn  (190S)  in  Genera  Insectorum  discussed  the  patterns 
from  a  somewhat  different  point  of  view.  He  states  that  in  the  ideal 
sense  the  markings  which  he  recognizes  as  the  humeral,  apical,  and 
middle  spots  are  made  up  of  3  humeral,  4  middle  and  3  apical  spots 
as  shown  in  figure  290,  plate  XV,  and  333,  plate  XVI.  Thus  he  calls 
the  markings  which  are  most  characteristic  of  the  group  the  Marginal 
Component.  He  calls  the  median  basal  spot  of  the  elytron  the  Basal 
Component  (Bl)  and  the  marking  along  the  suture  or  anal  border  of 
the  elytron  the  Sutural  Component.  He  recognizes  also  such  patterns 
as  those  sho\vu  in  figures  2-41,  243.  248,  as  Dis^pcrsion  Component.  He 
states  that  this  analysis  is  for  taxonomic  purposes  only  and  not  based 
on  ontogeny.  He  recognizes  the  most  important  tendencies  toward 
joining  of  spots,  in  addition  to  the  general  plan  outlined  in  G.  Horn's 
four  statements. 

The  work  of  these  men  is  here  cited  to  show  the  fact  that  various 
generalizations  have  already  been  made  sho^ving  that  the  patterns  eon- 
form  to  a  general  plan  of  spots  or  bands  which  have  been  similarly 
interpreted,  though  not  exactly  the  same,  by  two  authors  with  wide 
experience  in  the  group. 

For  the  purposes  of  illustrating  what  may  be  determined  in  the  / 
group  in  the  way  of  general  tendencies  (p.  36)    and    the    patterns    of 
interrttpta,   intcrrupta  subsp.   gahonica,  flexuo.ia    (PI.  XII),    tranque-   ; 
iarka.  and  purpurea.     And  for  a  second  illustration  take  the  same 
species  substituting  .^cutfUari.'i  for  purpurea. 

First  noting  interrupta  and  e/aionka,  (Figs.  156,  156  a  and  165, 
and  165  a)  one  finds  that  the  cross  bands  clearly  recognized  in  Coleop- 
tera,  especially  Chrysomelidae,  and  Lepidoptera.  and  which  appear  in 
the  tiger  beetle  group  especially  in  the  patterns  associated  with  inter- 
rupta (PI.  XII),  and  which  appear  in  all  the  species  in  which  ontogeny 
was  studied,  are  present.     In  gahonica  it  appears  that  through  iiidivid- 


60  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [454 

ual  variatiou  the  characteristic  joining  to  make  the  "middle  band"  is 
indicated.  This  occurrence  of  cross  bands  as  noted  and  the  variations 
of  interrupta  together  with  the  light  stripe  in  the  region  of  joining 
of  the  cross  band  4  with  cross  band  5.6  which  occurs  in  the  ontogeny 
of  the  patterns  of  scutellaris  constitute  the  evidence  for  the  line  of 
development  suggested. 

The  second  tendency  to  be  noted  is  the  shifting  of  the  spots  near 
the  sutural  or  anal  border  of  the  elytron  out  of  line  with  the  cross 
band  with  which  are  properly  associated.  This  is  sho^vn  in  figures 
156  and  156  a,  plate  XII,  interrupta  and  in  iigures  153  and  154  in 
flexuosa. 

The  third  tendency  to  be  noted  is  the  loss  of  the  three  small  baso- 
sutural  spots  {Bl,  C2.3,  D4,  Fig.  49,  PL  V).  This  usually  takes  place 
in  a  definite  order  if  individual  variation  may  be  trusted  as  an  indi- 
cator. At  least  these  may  have  disappeared  in  some  definite  order 
leaving  the  typical  pattern  of  tranquebari-ca  as  shown  in  the  controls 
of  the  experiments  (Figs  456a',  i'  and  457  a',  &').  This  type  is  shown 
in  figures  31,  32,  and  33,  plate  III,  and  the  elements  from  which 
it  is  made  are  shown  with  others  in  figure  49,  plate  V.  As  further 
evidence  of  the  longer  persistence  of  C3.4  see  figure  125,  plate  X,  and 
figure  145,  plate  XI,  which  are  late  stages  showing  the  persistence  of 
this  spot  after  the  more  anterior  one  has  disappeared. 

The  fourth  tendency  which  may  be  noted  is  the  tendency  for  the 
typical  C.  tranqueiarica  pattern  to  shift  as  indicated  in  the  patterns 
which  result  from  experimental  stimulation  during  ontogeny.  This  is 
shown  in  figures  456  a.  h,  457  a,  b,  458,  459,  and  460  a,  b,  plate  XXVIII. 
These  modifications  have  already  been  noted  on  page  39  but  may  be 
recalled  briefly  as  follows:  the  forward  and  backward  extensions  of 
the  inner  end  of  the  humeral  lunule  (spot  B2  di-ops  out)  disappear; 
the  slight  forward  extension  of  the  inner  end  of  the  middle  band  in 
the  longitudinal  stripe  C{C5)  drops  out  or  loses  identity.  The  with- 
drawal of  the  middle  band  from  the  elytral  margin  and  reduction  to 
conform  Math  that  of  C.  purpurea  (purpurea)  (Fig.  537,  PI.  XXVIII) 
is  the  striking  and  probably  the  most  important  change  best  illustrated 
in  460  ff,  b,.  Similar  modifications  in  all  high  temperature  experiments 
with  C.  hirticollis  (some  with  C.  limbalis)  serve  to  clinch  the  argument 
for  response  in  definite  directions. 

A  fifth  tendency  is  illustrated  by  C.  purpurea  as  shown  in  the 
figures  to  the  left  in  figure  537,  plate  XXVIII.  The  differences  be- 
tween the  purpiirea  series  and  the  tranquebarica  series  lies  in  the  short 
humeral  lunule  of  the  former,  which  indicates  a  different  tendency 
which  perhaps  constituted  the  original  distinction  between  the  patterns 
of  tlie  two  series. 


455]  COLORS  OF  TIGER  BEETLES—SHELFORD  61 

Turniug  to  the  scutellark  series  one  notes  that  markings  are  re- 
duced by  high  temperature  (Figs.  463  a,  &,-.  464  a,  6, -,  PI.  XX).  The 
original  markings  e\'ideutly  included  a  middle  band  like  purpurea 
(Fig.  512,  PI.  XXVIII).  As  e^•idenee  for  this  note  figure  490,  plate 
XXVIII,  which  shows  a  reduced  band  present,  and  figure  115,  plate 
IX,  which  shows  one  in  ontogeny  which  does  not  persist  in  tlie  adult 
at  all  in  individuals  from  the  central  states.  Stimulation  of  scutdlaris 
during  ontogeny  by  high  temperature  merely  reduces  the  markings 
concentriqly,  withdrawing  the  middle  band  from  the  margin  as  well  as 
from  the  centre.  This  is  the  type  of  modification  which  has  led  to 
immaculate  forms  in  the  south  and  southwest. 

Cold  extended  the  same  markings,  but  the  results  are  not  so  strik- 
ing in  general  plan  though  perhaps  equally  general  in  application,  as 
markings  are  lost  in  the  same  general  order  in  many  species  if  indi- 
vidual and  geographic  variation  may  be  used  as  an  indicator.  First 
we  have  noted  that  purpurea  is  divided  into  two  groups,  one  the  steep- 
bank-inhabiting  group  and  the  other  the  level-ground-inhabitant.  The 
latter  (PI.  XXV,  left,  and  PI.  XXVIII,  Fig.  537)  loses  its  markings  in 
the  manner  suggested  above,  as  indicated  by  the  experimental  results 
■nith  C.  tranquebarka^  The  outer  end  of  the  band  being  lost  first. 
The  other  loses  its  martriugs  as  does  C.  smtellaris.  Compare  486  to  490 
with  506  to  510  and  522  to  525,  plate  XXVIII.  which  indicate  the  loss  of 
markings  of  several  species  along  similar  lines,  i.e.,  through  retreat  to 
the  margin  and  then  reduction  of  the  marginal  markings.  Thus  the 
response  to  high  temperature  represents  a  tendency  present  in  many 
species. 

The  large  confluent  markings  of  Manitoba  specimens  and  of  those 
which  have  been  subjected  to  cold  suggest  that  a  second  type  of  re- 
sponse may  be  in  the  form  of  a  concentric  extension  of  the  unpigmented 
areas.  It  seems  e\'ident  that  the  mechanism  in  C.  scutellaris  may  be 
thrown  in  either  direction  from  the  general  average  of  the  species. 

I  have  followed  through  a  series  of  marking  modifications  and 
shown  evidence  for  the  tendencies  indicated.  It  would  be  futile  to 
present  further  discussions  of  a  similar  type  regarding  other  species, 
as  particidar  weight  is  given  to  experimental  results  and  such  results 
are  wanting  in  other  species.  Tlie  reader  by  an  inspection  of  the 
figures  which  are  particularly  numerous  and  selected  for  the  purpose 
will  note  that  in  many  groups  one  species  begins  in  pattern  modifica- 
tion where  another  leaves  off.  This  fact  was  noted  by  G.  Horn  (1892). 
In  many  cases  an  exact  knowledge  of  the  geographic  variation  of  the 
species  is  not  available,  but  figures  435  to  437,  plate  XVIII,  show  a  series 
which  is  supported  geographically.    C.  curvata  which  occurs  in  Mexico 


62  ILLLXOIS  BIOLOGICAL  MOSOGRAPHZ  [456 

is  first  ill  the  series,  dorsalis  saulcyi  which  occurs  iii  Texas  next,  and 
dormlis  which  occurs  in  New  York  and  New  England  shows  spreading 
of  the  white.  This  series  is  representative  of  one  in  which  the  patterns 
are  of  a  specialized  type,  in  which  the  media,  trachea  is  reduced.  For- 
ward curves  in  the  humeral  lunule  are  veVy  rare ;  one  specimen  of 
saulcyi  in  the  collection  of  Mr.  Gestroi  in  Genoa  has  this  marking 
curved  forward.  The  backward  curvature  occurs  also  in  trifasciata 
peruviana  but  is  rare.  Figure  434,  plate  XVIII  is  probably  this 
species. 

Much  detailed  study  and  collecting  is  necessary  to  show  that  the 
differences  which  enable  one  to  arrange  a  group  of  pattez'ns  in  series 
really  represent  a  series  geographically  or  habitudinally  separated,  and 
the  writer  refrains  from  further  discussion  of  such  cases  though  others 
might  be  cited  with  little  doubt  as  to  their  validity.  The  patterns  in 
the  illustration  pages  are  arranged  to  show  probable  lines  of  modifica- 
tion. The  large  series  of  parallel  trends  shown  in  different  groups 
leaves  little  doubt  that  the  tendencies  shown  are  highly  probable. 

Another  tendency  quite  common  in  the  Cicindelas  is  the  degener- 
ation of  the  media  trachea.  The  shifting  of  the  pattern  in  that  region 
is  one  of  the  first  modifications  to  take  place  if  we  may  judge  from  the 
existing  patterns  and  from  individual  variation.  The  complete  break- 
ing up  of  the  system  of  markings  appears  first  in  this  part  of  the 
elytron.  This  degeneration  of  the  old  system  of  markings  has  pro- 
ceeded far  in  some  species  such  as  figure  16,  nivea  and  figure  21, 
tenuipes.  Here  an  almost  entirely  new  system  has  grown  up,  but  de- 
rived from  the  older  one.  These  cases  constitute  our  best  evidence 
that  these  patterns  are  highly  specialized.  The  morphological  struc- 
tures with  which  the  pattern  is  associated,  are  modified ;  some  of  the 
important  parts  have  degenerated. 

In  considering  these  patterns  and  the  modifications  which  take 
place  the  reader  must  not  fail  to  note  that  there  are  physieological 
problems  to  be  considered  and  physiological  work  to  be  done.  The 
explanation  for  the  occurrence  of  pigment  in  some  parts  of  the  body 
and  not  in  others  may  be  very  simple.  In  course  of  experiments  con- 
cerned with  the  production  of  abnormalities,  it  was  found  that  the 
labrum  which  is  not  pigmented  in  the  species  used,  develops  pigment 
in  the  area  of  wounds.  Specimens  with  abnormal  elytra  which  appear 
to  be  due  to  injury  or  irritation  nearly  always  have  reduced  patterns, 
but  no  cases  in  which  the  white  markings  are  extended  are  recorded. 
Tlras  it  appears  that  the  present  adult  areas  of  pigmentation  and  areas 
of  ontogenetic  and  earlier  pigmentation  may  be  merely  areas  occupied 
by  cells  with  a  higher  rate  of  metabolism.     This  in  the  normal  elytron 


457]  COLORS  OF  TIGER  BEETLES— SHELFORD  63 

may  be  due  to  advantageous  nutrition  conditions  arising  from  the  mor- 
pliology  of  the  wing,  or  to  special  characteristics  of  the  cells  themselves. 

BEARING    OF    THE    COLOR    PATTERN    MECHANISM    ON    ORTHOGENESIS 

Orthogenesis  is  commonly  understood  as  evolution  in  certain  direc- 
tion as  opposed  to  evolution  due  to  the  survival  of  certain  kinds  of 
variations  out  of  a  large  fortuitous,  series.  The  chief  points  in  the 
original  contention  of  Eimer,  namely,  that  progress  in  species  formation 
has  been  along  definite  lines,  has  been  so  generally  admitted  that  the 
remaining  matters  are  concerned  with  such  questions  as:  Hoav  definite 
have  the  directions  of  modification  been?  What  are  the  causes  of  cer- 
tain-directions of  modification  being  developed  to  the  exclusion  of 
others?  Are  the  causes  external  or  internal?  Whitman  has  empha- 
sized the  internal  causes,  which  is  the  tendency  of  all  who  come  at  the 
problem  from  the  point  of  view  of  embrj'ology,  cytolog.y,  and  modern 
genetics.  The  mystical  nature  of  the  question  of  the  origin  of  a  com- 
'i  \  plex  organism  from  a  single  cell,  transmitted  through  the  egg  and  the 
'  /  sperm  of  tlie  entire  series  of  details  which  are  inherited,  have  fascinated 
men  and  led  to  the  general  acceptance  of  theories  which'  involve  the 
insulation  of  the  bearers  of  herditary  characters  from  the  environment. 
The  evidence  at  hand  does  not  justify  any  detailed  discussion  of  this 
problem  but  I  will  turn  to  the  few  things  which  appear  to  apply  to 
the  tiger  beetle  group. 

The  effects  of  high  temperature  on  tranqucbarica  produce  varia- 
tions in  the  direction  of  shortening  the  longitudinal  portion  of  the 
middle  band  and  throwing  this  marking  into  an  oblique  position.  This 
is  also  one  of  the  general  tendencies  in  a  large  group  of  tiger  beetles. 
In  tranqufharica  it  occurs  as  a  response  to  stimulation,  and  in  its  races 
of  luiknown  stability  in  regions  in  which  high  soil  temperatures  may 
be  expected.  It  occurs  in  nearly  half  the  species  of  the  group  of  tiger 
beetles  as  a  regular,  probably  hereditary  character.  Tlie  condition  of 
the  middle  band  seems  to  be  due  to  a  mechanism  of  response  or  modi- 
fication, which  is  the  same  in  these  responses  to  stimuli  and  in  the 
regular  heredity  trends.  The  problems  of  herdity  then  appear  to  be 
the  same  as  the  problems  of  development  and  modification  of  this 
elytral  character  of  Cicindela.  Perhaps  the  weakest  point  in  the  en- 
tire method  of  study  and  reasoning  of  tliose  interested  in  problems  of 
heredity  is  tlie  apparent  practical  assumption  that  laws  of  heredity 
are  not  the  same  as  laws  governing  characters,  in  particular  organs, 
and  as  laws  of  response.  Tlie  evidence  presented  tends  to  show  that 
these  laws  are  one  and  the  same  and  are  dependent  upon  a  mechanism 
present  in  the  elyti*a  of  many  species  of  Cicindela.     If  tliis  is  what  is 


64  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [458 

meant  by  ortliogensis  this  group  illustrates  the  orthogenetie  priuciijle. 

The  illustration  above  is  concerned,  however,  with  oul.y  one  of  sev- 
eral kinds  of  tendencies  which  appear  in  the  group.  Still  another 
Ijrinciple  is  suggested  by  the  experiments.  If  extension  of  the  unpig- 
mented  areas  is  indicated  by  the  experiments  with  cold  conditions  dur- 
ing ontogeny,  which  would  be  supported  by  geographic  variation  in 
many  species,  one  is  forced  to  the  conclusion  that  different  kinds  of 
stimuli  acting  on  the  pattern  mechanism  produce  different  responses. 
One  type  of  response  is  the  extension  of  the  unpigmented  ai"eas.  From 
an  inspection  of  the  figures  it  appears  that  this  may  take  place  on  the 
basis  of  a  pattern  in  any  stage  of  reduction.  As  a  rule  it  occurs  in  cor- 
relation with  some  marked  change  in  the  basal  structures  of  the  elytron 
at  least  when  the  extensions  violate  the  original  plan  of  the  pattern. 
The  mechanisms  of  pattern  heredity  and  pattern  development  possess 
the  capacity  both  to  respond  to  stimuli  by  changes  in  form  and  by  the 
extension  of  the  unpigmented  areas.  This  extension  of  the  unpigmented 
areas  may  take  place  in  almost  any  form  of  pattern  shown  in  the  entire 
series  and  may  be  concentric  or  in  part  linear.  This  is  shown  in  plates 
XII  to  XVIli  and  XXXVIII.  The  concentric  extension  at  least  would 
seem  to  constitute  a  sort  of  reverse  principle  to  that  illustrated  by 
the  changes  in  form  resulting  from  my  experimental  conditions,  such 
as  high  temperature.  In  dealing  with  definite  directions  of  response 
which  may  be  termed  orthogenetie  if  desired,  one  must  recognize  pro- 
gressive modification  on  the  basis  of  a  mechanism  which  may  move  in 
any  one  of  two  or  three  or  more  directions  under  the  stress  of  external 
stimuli.  Some  evidence  for  a  progressive  series  of  modifications  in 
the  same  direction  running  through  a  series  of  species  in  the  tiger 
beetles  is  afforded  by  the  experimental  results.  In  general  tlie  pattern 
of  C.  hirticollis  is  more  angular  and  as  a  whole  conforms  to  the  original 
groimd  plan  better  than  tliat  of  C  tranquebarica.  The  modification  of 
the  patterns  (middle  band)  of  C.  hirticollis  is  in  a  direction  toward 
that  of  C.  tranqueharica,  but  is  not  carried  so  far  as  are  the  modified 
patterns  of  C.  tranqueharica.  C.  limhalis  is  usually,  in  the  less  modi- 
fied forms  of  middle  band,  about  as  far  from  the  original  angular  type 
as  are  the  more  modified  forms  of  C.  tranquebarica.  Stimulation  of 
the  mechanism  of  the  middle  band  in  limbalis  at  this  stage  usually 
throws  the  band  still  further  toward  that  of  splendida  or  typical  pur- 
purea (Fig.  .537,  PI.  XXVIII).  Since  the  middle  bands  of  the  three 
species  differ  normall.y  only  in  the  extent  to  which  such  oblique  shift- 
ing occurs,  and  each  differs  from  the  original  plan  to  a  greater  degree 
than  the  other,  the  peculiar  character  of  the  direction  taken  must  re- 
sult from  a  similarity  of  mechanism  in  tlie  different  species  concerned. 
Abundant  evidence   for  stages   in   such   shifting    as    fixed    hereditary 


459]  COLORS  OF  TIGER  BEETLES—SHELFORD  65 

characters  is  found  iu  many  patterns  illustrated  in  the  plates,  particu- 
larly plate  XXXVIII.  The  series  of  three  species  thus  show  the  same 
tendency,  with  respect  to  the  middle  band.  This  must  be  due  to  the 
existence  of  the  same  mechanism  for  heredity  and  response.  The  next 
step  to  important  discovery  probably  lies  in  the  direction  of  further 
analysis  of  the  mechanism  by  experimental  means,  which  may  include 
surgical  and  mechanical  experiments  on  the  developing  wing  covers, 
and  analysis  by  such  methods  are  commonly  used  by  the  breeder. 

BEARIXG  OF  THE  PATTERN   MECHANISM  ON  THE  BIOGENETIC  LAW 

The  data  accumulated  in  connection  with  this  study  shows  certain 
principles'''coficerned  with  the  application  of  the  biogenic  law.  First 
the  general  plan  of  the  pattern  seems  to  be  common  to  all  insects.  The 
ancestry  of  the  insect  group  is  too  obscure  to  justify  the  assumption 
that  any  original  ancestor  possessed  a  wing  with  nineteen  spots  such 
as  arei  shown  in  the  elytron  of  Cicindela,  or  that  such  an  ancestor 
possessed  longitudinal  stripes  or  cross  bands.  The  evidence  seems  to 
indicate  that  the  tiger  beetle  group  sliows  a  type  of  pattern  mechan- 
ism described  at  length  in  the  preceding  pages;  that  this  pattern 
mechanism  is  plastic  at  least  in  the  more  generalized  species;  that 
from  this  plastic  mechanism  certain  definite  lines  of  modification  have 
been  somewhat  fixed  and  limited.  So  long  as  the  ontogeujie  features 
are  concerned  with  the  general  mechanism  one  is  not  justified  in  calling 
the  appearance  of  certain  spots  recapitulations.  They  may  full.v  as 
well  be  areas  which  are  less  favorably  nourished  or  which  are  made  up 
of  cells  with  lower  rates  of  metabolism  (see  p.  31).  Either  of  these 
physiological  conditions  may  be  due  to  mechanical  necessities  in  devel- 
opment in  all  insects  primitive  and  specialized,  and  if  so,  why  call  them 
recapitulations  1 

Such  evidences  of  recapitulation  as  do  occur  are  found  in  the  re- 
currence of  markings  in  development  which  represent  those  occurring 
in  related  species  or  varieties.  Thus,  as  I  have  noted,  a  curved  middle 
band  occurs  in  the  ontogeny  of  some  specimens  of  C.  Iccontri  and  du- 
plicates a  late  stage  in  the  loss  of  this  marking  as  sho^ni  in  figure  115, 
plate  IX.  Here  a  curved  and  degenerate  form  of  this  marking  occurs 
temporarily  during  ontogeny  and  may  perhaps  be  regarded  as  recapitu- 
lation. The  application  of  the  biogentic  law  must  generally  be  fol- 
lowed with  great  caution  in  dealing  with  insect  patterns  and  no  doubt 
with  many  other  phenomena. 


66  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [-WO 


SUMMARY   OP    CONCLUSIONS 


1.  The  color  patterns  of  the  tiger  beetles  are  related  to  elytral 
structures  but  not  casually;  longitudinal  stripes  in  which  pigment  usu- 
ally occurs  lie  in  the  area  of  the  chief  tracheal  trunks ;  there  are  seven 
cross  bands  in  which  pigment  does  not  develop,  the  second  and  third 
and  fifth  and  sixth  of  these  are  often  joined  to  make  one  of  each  pair. 

2.  Pigment  usually  occurs  about  the  bases  of  hairs  which  usually 
lie  in  the  lines  of  the  tracheae. 

3.  In  ontogeny  the  elytra  show  a  spotted  condition  corresponding 
to  the  system  of  cross  bauds  and  longitudinal  stripes.  The  longitudinal 
stripes  are  usually  more  pronounced. 

4.  The  characteristic  markings  of  the  group  are  composed  of  spots 
or  elements  joined  in  the  longitudinal  light  stripe  areas  and  areas  of 
cross  bands  with  the  loss  of  various  spots  or  elements  which  occur  in 
ontogeny;  joinings  are  sometimes  oblique  and  when  so  markings  are 
sometimes  parallel  with  curved  end  of  the  elytron. 

5.  Certain  particular  types  of  markings  made  up  of  a  few  elements 
joined  in  a  particular  way  characterize  the  majority  of  species  of  the 
group. 

6.  These  markings  as  derived  from  the  cross  and  longitudinal 
bands  are  angular;  reduction  of  angles,  straightening  and  turning  into 
oblique  positions  parallel  with  the  end  of  the  elytron  characterize  modi- 
fications of  markings.  The  response  to  stimuli  (high  temperature)  is  in 
the  same  direction. 

7.  Response  to  other  stimuli  appeal's  to  be  in  tlie  direction  of 
concentric  extension  of  the  markings. 

8.  The  color  patterns  and  structure  to  which  they  are  related 
constitute  a  mechanism,  the  directions  of  movement  of  which  are  lim- 
ited, i.e.,  easier  in  some  directions  than  others;  the  color  pattern  plans 
bi-eak  when  the  related  structures  do;  hereditary  changes  and  fluctua- 
tions due  to  stimvilation  during  ontogeny  are  in  the  same  direction; 
laws  governing  the  mechanism  are  the  same  throughout. 

9.  These  laws  when  applied  to  hereditary  changes  are  apparently 
what  is  sometimes  termed  orthogensis. 

10.  It  is  not  correct  to  assume  that  all  manifestations  of  the 
■wing  mechanism  which  appear  during  ontogeny  follow  the  biogenetic 
law. 


461]  COLORS  OF  TIGER  BEETLES— SHELFORD 


1.  The  brilliant  colors  of  the  group  are  due  to  thin  surface  films 
of  material  having  properties  of  metals. 

2.  Changes  in  color  during  ontogeny  are  from  green  and  blue  toward 
red  or  brown,  except  in  C.  lepida  in  which  it  is  from  yellow  (gold) 
to  green;  purples  appear  to  stand  apart  from  greenish  blues  and  do 
not  change  diiring  ontogeny  or  if  so  only  slightty. 

3.  During  ontogeny  some  species  pass  through  stages  correspond- 
ing to  geographic  races,  but  the  biogentic  law  is  of  doubtful  applica- 
tion, though  green  stages  in  ontogeny  possess  the  same  amount  of  pig- 
ment as  green  races  and  the  reds  and  brown  which  come  later  are  as- 
sociated with  more  pigment  but  not  causally. 

GEOGEiVPHY 

1.  The  center  of  distribution  of  the  group  is  about  the  Indian 
Ocean. 

2.  Geographic  races  and  geographic  distribution  Js^uot  correlated       .A.^-^  ■ 
with  any  observed  climatic  or-  meteorological  conditions  unless  it  be 
rainfall  and  in  this  case  the  correlation  is  not  complete.     This  lack  of 
correlation  is  believed  to  be  due  to  a  lack  of  records  of  soil  conditions. 

3.  Experimental  modifications  nearly  duplicate  certain  geographic 
races  of  the  species  concerned ;  these  races  occur  in  localities  where 
conditions  are  probably  similar  to  the  experimental  condition. 

4.  In  the  species  studied  in  detail  the  more  brilliant  colors  are 
in  warm  arid  localities,  reduced  marking  in  warm  localities,  and  ex- 
tended marking  in  cooler  localities. 


68  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [462 


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1912.  Ecological  Succession,  IV.  Vegetation  and  the  Control  of  Land  Com- 
munities.    Biol.  Bull.,  23:59-99. 

1912a.  Ecological  Succession,  V.  .Aspects  of  Physiological  Classification. 
Biol.  Bull.,  23:331-370. 

1913.  Noteworthy  Variations  of  the  Elytral  Tracheatinn  of  Cicindcla.  Ent. 
News.  24:124-125. 

1913a.  The  Life-History  of  a  Bee-Fly  (Sl'ogostyltim  anale.  Say)  Parasite 
of  the  Larva  of  a  Tiger-beetle  (Cicindcla  scutcltaris  lecontei,  Hald.) 
.Amer.  Ent.  Soc,  6:213-225. 


70  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [464 

Shelford,  V.  E.   (continued) 

1913b.    Animal    Communities   in    Temperate   America   as    Illustrated   in   the 
Chicago  Region.     A  Study  in  Animal  Ecology.     380  pp.     Chicago. 

1914.  Abnormalities    and    Regeneration     in    Cicindela.      Amer.     Ent.    Soc, 
8:291-295. 

1915.  Elytral  Tracheation  of  the  Tiger  Beetles   (Cicindelidae').     Tr.  Amer. 
Micr.  Soc,  34:241-254- 

Tower,  W.  L. 

1903.  Origin  and  Development  of  the  Wings  of  Coleoptera.     Zool.  Jahrb., 
Anat.,  17:517-572. 

1903a.     Colors  and  Color  Pattern  of  Coleoptera.     Dec.  Publ.  Univ.  Chicago, 

(i)  10:33-70- 
1906.    An  Investigation  of  Evolution  in  Chrysomellid  Beetles  of  the  Genus 
Leptinotarsa.     Carnegie  Inst.  Wash.,   Publ.  48. 
Whitman,  C.  O. 

1904.  The   Problem  of   the    Origin   of    Species.     Cong,   of   Arts   and    Sci., 
Universal  Exposition,  St.  Louis,  5  :4i-58. 

WiCKHAM,  H.   F. 

1902.     Habits  of  American   Cicindelidae.     Proc.  Davenport  Acad.   Nat.  Sci., 

7 :  206 -228. 
1904.     The   Influence  of   the   Mutations  of  the   Pleistocene  Lakes   upon   the 
Present  Distribution  of  Cicindela.    Amer.  Nat.,  38 :643-654. 

1906.  The  Races  of  Cicindela  tranqKcbarica  Herbst.     Ent.  News,  17:43-48. 
Zeleny,  C. 

1907.  The  Direction  of  Differentiation  in  Development.     The  Antennule  of 
Mancasellus  macroyrus.    Arch.  Entw.  ]\Iech.  Org.,  23  :324-343. 


465]  COLORS  OF  TIGER  BEETLES— SHELF ORD 


EXPLANATION    OF    PLATES 

Because  of  the  diversity  of  material  studied,  the  plates  of  this 
monograph  have  been  made  in  different  ways  and  for  details  and  excep- 
tions to  the  general  statements  below  it  will  be  necessary  to  see  the  text. 
Plates  I  to  IV  show  camera  drawings  made  chiefly  by  mounting  dry 
elj^ra  in  hot  balsam  containing  little  or  none  of  the  usual  solvents. 
Plate  V  is  a  diagram.  Plates  VIII  to  XI  were  made  from  specimens 
killed  in  the  best  of  fixing  fluids  and  mounted  according  to  approved 
methods.  They  represent  different  indi\'iduals  chosen  at  different 
stages,  but  have  been  checked  with  individual  histories.  Plates  VI,  VII, 
and  XII  to  XXVIII,  in  so  far  as  they  are  concerned  with  eh-tra,  are 
made  up  of  free-hand  drawings  of  elytra  as  seen  from  directly  above 
the  center  of  the  curved  side,  i.  e.  to  the  left  and  above  the  specimen. 
The  specimens  represented  are  from  various  sources.  All  are  dra^ni 
the  same  size  though  the  specimens  vary  greatly.  The  drawings  in 
plates  XII  to  Xr\"III  are  about  twice  the  natural  size  of  an  average 
species.  The  distribution  data  shown  were  supplied  from  various  col- 
lections and  printed  lists.  The  colored  plates  which  show  color  ontogeny 
were  made  chiefly  from  the  same  living  individual. 


72  ILLIXOIS  BIOLOGICAL  MOXOCRAPHS  [466 


PLATE  I 


Explanation  of  Plate 

Figure  i.  Cross  section  of  the  adult  elytron  of  C.  lepida,  showing  the  re- 
lation of  lack  of  pigment  to  interlamellar  spaces.  The  portion  at  the  right  is 
through  a  pigmented  area  and  that  at  the  left  through  an  unpigmented  area.  PCU, 
primary  cuticula,  unpigmented ;  PCP,  primary  cuticula,  pigmented ;  SC,  secondary 
cuticula.  The  portion  under  the  unpigmented  areas  is  divided  into  layers  sepa- 
rated by  air-tilled  spaces  above  which  small  canals  project  into  the  layer  above ; 
under  the  pigmented  part  the  cuticula  is  in  clear  layers  with  no  spaces  between. 
The  air  spaces  in  the  cuticula  imder  the  unpigmented  portion  are  probably  the 
cause  of  the  appearance  resembling  white  pigment  in  the  unpigmented  areas. 

Figures  2-9.  Showing  the  relation  of  the  markings  and  tracheae  in  Cicindela. 
The  tracheae  present  are  from  left  to  right  casta.  (Co)  (see  Fig.  21),  the  subcosta 
(S),  the  radius  (R),  the  media  (M),  and  the  cubitus  (Cu).  The  anal  cannot  ordi- 
narily be  demonstrated  in  dried  elytra.  The  drawings  were  made  with  a  camera 
lucida.  The  figures  indicate  a  number  of  unpigmented  areas  which  are  in  the 
form  of  cross  bands  which  may  be  broken  by  the  pigment  lying  in  the  lines  of 
the  tracheae ;  the  letters  A,  B,  and  C  indicate  the  unpigmented  stripes  to  fall  be- 
tween the  tracheae. 

Fig.  2.  C.  rcgalis  Dej.  (Africa)  :  3,  intcrrupta  Fabr.  (Africa)  ;  4,  intcr- 
rupta  Fabr.  (Africa)  ;  5,  dongalensis  Klg.  (N.  Africa)  ;  6,  vigintiguttaia  Herbst. 
(India);  7,  compressicornis  Boh.  (Africa);  8,  comprcssicornis  Boh.  (Africa);  9, 
discrepans  Walk.   (Ceylon). 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 
PCU 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  I 


74  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [468 


PLATE  II 


Figures  10-21.  Showing,  the  close  correlation  between  the  distribution  of 
tracheae  and  dark  pigment  in  the  more  specialized  patterns  of  Cicindela.  Figures 
10  to  22  show  close  conformation  of  color  patterns  and  tracheae.         » 

Explanation  of  Plate 

Fig.  10.  C.  striolata  Illig.  (India)  ;  11,  cincta  Oliv.  (Africa)  ;  12,  anchoralis 
Chvr.  (S.  China)  ;  13.  quadrilineata  Fabr.  (India)  ;  14,  capensis  Linn. — the  costa 
and  subcosta  were  probably  present  but  could  not  be  demonstrated;  15,  capensis 
Linn.  sub.  sp.  chrysographa  Dej.  (S.  Africa)  ;  16,  nivea  Kirb.  aber  conspersa 
Dej.,  showing  reduction  of  the  media  (S.  America)  ;  17,  painphila  Lee.  (S.  U.  S.)  ; 
18,  lugubris  Dej.  (Africa);  19,  gabbi  G.  Horn  (S.  W.  U.  S.)  ;  20,  dorsalis  Say 
(Coast  of  U.  S.  A.)  ;  21,  tcnuipes  Dej.  (India),  Co,  costa,  S,  subcosta,  R,  radius. 
M,  media,  Cu,  cubitus. 


ILLISOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  II 


76  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [470 


PLATE  III 


Figures  22-33.  Showing  the  transverse,  longitudinal,  and  oblique  bands  in 
Ctenostomidae  Collyridae;  Cicindelidae  (Dromicini  and  Odontochilini)  and  va- 
riations in  the  markings  of  C.  tranquebarica,  a  species  with  typical  patterns  and 
variations. 

Explanation  of  Plate 

Fig.  22.  C.  longipes  Fabr.  (Malay  Arch.)  ;  23,  imperfecta  Lee.  (S.  W.  U. 
S.)  ;  24,  luteolineata  Chvr.  (Mexico) ;  25,  lemniscata  Lee.  (S.  W.  U.  S.)  ;  26, 
Ctenostoma  obliguatum  Chd.  (South  America),  showing  the  central  transverse 
band  and  distal  spot;  27,  Ctenostoma  unifasciatum  Dej.  (S.  America)  ;  28,  Collyris 
celebensis  Chd.  (Malay  Arch.),  showing  three  lighter  cross  bands;  29,  Heptodonta 
analis  Fabr.  (India),  showing  spots  representing  two  cross  bands;  30,  Dromica 
coarctata  Dej.  (S.  Africa),  showing  longitudinal  stripes  and  heavier  pigment  in 
the  lines  of  the  tracheae;  31-33,  showing  patterns  of  C.  tranquebarica  Herbst 
(N.  A.),  typical  pattern  (31)  and  extended  pattern  with  extensions  between  the 
tracheae  (32),  and  a  reduced  pattern  (33)  with  the  middle  marking  broken  in 
the  line  of  the  trachea. 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


4- 


27     p 


^1 


COLORS  OF  TIGER  BEETLES 


PL\'IK  III 


ILLINOIS  BIOLOGICAL  MONOGRAPHS  [472 


PLATE  IV 


Figures  34-38.  Showing  the  relation  of  the  tracheae  to  pigmentation  of  the 
elytra  in  Carabidae  and  Dytiscidae. 

Explanation  of  Plate 

Fig.  34.  Omophron  sp.  (N.  A.),  showing  suggestions  of  transverse  bands  num- 
bered to  correspond  with  figures  66  and  67  and  a  tendency  for  white  markings 
between  the  bands  to  lie  between  the  tracheae ;  35,  Benibidium  versicolor  Lee. 
(Illinois),  showing  the  unpigmented  areas  in  the  lines  with  the  tracheae;  36, 
unknown  carabid  (Amazon),  showing  the  pigmented  areas  in  the  lines  of  the 
tracheae;  37,Nebia  coiiiplanata  Linn.  (Europe),  showing  a  tendency  to  lines  over 
the  tracheae  and  between  them;  38,  Hydacticus  stagnalis  Fabr.  (Illinois),  show- 
ing double  lines ;  39,  Laccophilus  ntaculosus  Say,  showing  the  transverse  bands 
and  suggestion  of  double  unpigmented  lines  with  the  tracheae  in  the  pigmented 
areas  (see  Fig.  18)  ;  40,  Agabits  tacniolatus  Harr.  (Illinois),  showing  trachea  in 
the  unpigmented  areas  with  a  suggestion  of  double  lines ;  41,  Hydroporus  undn- 
latiis  Say  (Illinois),  showing  the  cross  bands — a  suggestion  of  all  those  commonly 
present  in  Cicindcla. 


ILLINOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


COLORS  OF  TIGER  BEETLES 


PLATE   IV 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [474 


PLATE  V 

Figures  42-49.     Showing  an  analysis  of  the  color  patterns  of  Cicindela. 
Explanation  of  Plate 

Fig,  42.  Showing  the  full  number  of  longitudinal  stripes  represented  in  the 
group — compare  with  figures  169,  169a,  and  169^  Uctragraiiuna  Boisd.)  ;  43,  show- 
ing the  three  longitudinal  stripes  nearly  always  represented — compare  with  52 
(C.  tetragramina,  variation)  and  54,  desgodinsi  Fair  (Tibet);  44,  showing  the 
splitting  of  the  stripes  as  suggested  in  53,  lugubris  Dej.  (Africa)  ;  45,  showing 
the  full  number  of  cross  bands  numbered  /  to  7;  46,  showing  the  commonest 
cross  bands  illustrated  in  58  (rcgalis  Dej.  Africa)  ;  47,  showing  a  second  com- 
mon type  illustrated  by  75,  in  which  none  of  them  reach  clear  across :  48,  show- 
ing all  the  possible  spots  that  can  occur  from  a  combination  of  the  longitudinal 
stripes  and  cross  band  shown  in  figures  42  to  47 ;  49,  showing  the  spots  which 
are  most  commonly  present  or  joined  to  form  characteristic  patterns  in  the  group. 

A  and  a  are  usually  fused  on  account  of  the  crowding  together  of  the 
traclieae.  The  cross  bands  are  never  all  represented  entirely  across  the  elytron, 
but  by  dots  as  in  62,  C.  vigintiguttata  Herbst  (India).  The  fusion  of  Ai,  As 
and  Bs  gives  the  characteristic  humeral  lunule  of  students  of  the  group,  the  hook 
frequently  present  is  made  by  joining  it  with  B^.  The  fusion  of  Ci  and  Cs  and 
of  C3  and  C4  gives  the  characteristic  markings  shown  in  the  line  C.  of  many  old 
world  species.  The  union  of  A4,  B4  and  5.5  gives  the  characteristic  middle  band 
of  the  group.  As  is  of  rare  occurrence  (see  Fig.  198).  .J5  is  commonly  present 
as  a  spot,  also  A6,  B6  and  C6  are  less  common  in  occurrence  (see  Figs.  6  and  7, 
PI.  I). 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


COLORS  OK  TIGER  BEETLES 


82  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [476 


PLATE  VI 


Figures  50-77.  Showing  selected  Cicindelid  patterns  with  lines  to  show  the 
correspondence  of  all  the  chief  types  of  pattern  to  the  plan  shown  in  Plate  V. 

Explanation  of  Plate 

Figs,  so,  51,  52,  C.  tctragramma  Boisd.  (Australia)  ;  53,  lugubrus  Dej.  (Af- 
rica) ;  54,  desgodinsi  Fair  (Tibet)  ;  55,  interruptofasciata  Schm.  (Siam)  ;  56,  inuata 
sub.  sp.  laticornis  Horn  (Africa)  ;  57,  coinpressicornis  Boh  (Africa)  ;  58,  rcgalis 
Dej.  (Africa)  ;  59,  atkinsoni  Gestro  (Australia)  ;  60,  regina  Kolbe  (Africa)  ;  61 
melaleuca  Dej.  (S.  A.)  ;  62,  vigintignttata  Herbst  (India)  ;  63,  notata  Boh  (Af- 
rica) ;  64,  gcrstacckcri  Horn  (Africa)  ;  65,  Euryoda  adonis  subsp.  rufosquata 
Bell  (Madagascar),  Boh;  66,  damcnsis,  (Siam);  67,  Odontochila  singularis  Fit. 
(S.  A.)  ;  68,  Peridexia  hilaris,  Fajrm.  (Madagascar)  ;  69,  flavosignata,  Cast,  (Af- 
rica) ;  70,  crespigjiyi  Bates  (Borneo)  ;  71,  anchoralis  Schm.  (China)  ;  ^2,  copulata 
Schm.  (India)  ;  73,  interriipta  subsp.  gahonica  Bat.  (Africa)  ;  75,  aphrodisia 
Baudi   (Cypris)  ;  76,  aurtdenta  Fabr.   (India);  77,  6  punctata,  Fabr.    (India). 


IIJJXOIS  BIOLOGICAL  MOSOCRAPHS 


VOLUME  3 


SHELFORD 


73"    '   '       74"    '   '        75'  '    ■  76' 

COLORS  OF  TIGER  BEETLES 


77' 
PLATE  VI 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [478 


PLATE  VII 


Figures  78-98.  Showing  some  of  the  chief  lines  of  union  of  markings  not 
indicated  on  the  preceding  chart. 

Explanation  of  Plate 

Fig.  78,  showing  the  spots  which  enter  into  the  patterns  with  some  of  the 
characteristic  unions  indicated — the  stippled  areas  refer  to  figures  79  and  80; 
the  narrow  white  lines  to  81,  82,  and  83;  the  dotted  lines  to  88  and  89,  and  90  and 
91;  79,  apiata  dausseni  Putz  (S.  A.)  ;  80,  striolata  subsp.  trisignata  Chd.  (India)  ; 
81,  fatidica  Guer  (Africa)  ;  82,  (Prodotcs)  miinula  Per.  (Africa)  ;  83,  viridis 
Raffr.   (Africa);  84,  pdetieri   (N.  Africa). 

Figs.  85-87.  Showing  the  oblique  shifting  of  the  cross  markings ;  85,  regalis 
Dej.  (Africa)  ;  86,  andriana  All  (Africa)  ;  87,  maheva  Kunck  (Africa)  ;  88,  cey- 
lonensis  Horn  (India)  ;  89,  oscari  Horn  (Africa)  ;  90,  kolbci  Horn  (Africa)  ;  91, 
princeps  ducalis  Horn  (India)  ;  92,  longipes  Fabr.  (Malay  Arch.)  ;  93,  albicans 
Chd.  (Australia)  ;  94,  nitida  Wdm.  (India)  ;  95,  trisignata  Dej.  (Europe)  ;  96, 
nitidula  Dej.  (Africa)  ;  97,  gahhi  S.  Horn  (S.  W.  U.  S.  A.)  ;  98,  Icuconoe,  Bates 
(Mexico). 

Figures  99-100.  Showing  the  color  areas  of  the  larvae  for  comparison  with 
figures  101  to  105.  Ventral  side  of  the  abdominal  segment  of  a  larva  of  C.  tran- 
qucbarica.  The  areas  are  lettered  as  in  figure  loi ;  100,  showing  the  color  centers 
of  the  dorsal  side  of  a  larva.  Compare  with  figure  loi.  The  area  with  the  spira- 
cles is  the  pleuron. 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


SHELFORD 


99  100 

COLORS  OF  TIGFR  BEETLES  PLATI-.  VI I 


86  ILLISOIS  BIOLOGICAL  MONOGRAPHS  [480 


PLATE  VIII 


Figures  ioi-iio.  Showing  the  development  of  pigment  in  the  legs  and  body 
of  C.  tranguebarica,  Herbst. 

Explanation  of  Plate 

Figures  loi-iio.  Showing  the  pigment  beginning  at  the  posterior  end  of  the 
body  and  moving  forward  except  the  trochanters  which  are  pigmented  at  emer- 
gence; loi,  3  to  6  hours  after  emergence;  102,  8  to  12  hours;  103,  12  to  15  hours; 
104,  24  to  36  hours.  A,  anterior  band  of  pigment  on  the  segment;  /,  the  posterior 
band  of  the  segment;  aa,  the  large  central  anterior  area — compare  with  figure  105. 

Figs.  105-108,  showing  the  development  of  pigment  in  the  dorsal  side  of  the 
abdomen;  105,  at  emergence,  showing  the  large  dorsal  spots  beginning  of  tlie 
posterior  segments ;  105a,  after  3  to  6  hours,  showing  the  fusion  of  the  spots 
toward  the  center ;  106,  8  to  10  hours  after  emergence,  showing  the  nearly  com- 
plete abdominal  pigment,  the  beginning  of  the  pigmentation  of  the  thorax,  and 
the  lines  on  the  head;  107,  showing  the  increase  in  the  head  and  thoracic  regions 
at  12  to  15  hours  after  emergence;  108,  showing  the  dorsal  side  of  the  head  and 
thorax  after  24  to  36  hours;  109  o  to  d,  the  antenna;  3  hours  after  emergence; 
h,  6  hours  after  emergence;  c  at  8  to  10  hours  after  emergence;  d,  11  to  15  hours 
after  emergence;  c,  24  hours  after  emergence;  no,  a,  showing  the  hind  leg  three 
days  after  emergence;  b.  at  emergence;  c,  after  6  to  8  hours;  d,  12  hours  after 
emergence. 


ILLISOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  VIII 


88  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [482 


PLATE  IX 


Figures  111-122.  Showing  stages  in  the  development  of  pigment  in  the 
elytron  of  C.  repanda  Dej.  and  C.  scutellaris  aber  lecontei  Hald. 

Explanation  of  Plate 

Fig.  Ill,  4  to  S  hours  after  emergence,  showing  the  longitudinal  lighter  areas 
corresponding  to  A,  B,  C  of  the  preceding  figures;  112,  after  12  to  15  hours, 
showing  the  stripes  A,  B,  C  broken  into  cross  bands,  3  and  4  being  clearly  indi- 
cated in  the  stripe  C;  114-118,  showing  stages  in  the  development  of  the  elytral 
pigment  in  C.  scutellaris  lecontei  Hald;  114,  after  4  to  5  hours;  115,  after  12 
hours,  showing  particularly  a  well  indicated  cross  band  not  appearing  in  the 
adult;  116,  after  15  hours,  showing  well  marked  longitudinal  bands  broken  in 
spots;  117,  after  36  hours  with  similar  marking  indicated;  118,  after  36  hours, 
similar  to  117;  119,  the  hind  wing  at  emergence;  120,  after  12  hours;  121,  after 
^6  hours;  122,  adult. 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


COLORS  OF  TIGER  BTiETLES 


PLATE  IX 


ILLIXOIS  BIOLOGICAL  MOXOCRAl'IIS  [484 


PLATE  X 


Figures  123-134.  Showing  stages  in  the  development  of  the  pigment  of  the 
elytra  of  C.  purjmrea  limbalis  Klg.  (123-130),  and  in  C.  tranguebarica  Herbst 
(131-134).  The  wing  areas  are  indicated  bj'  letters  and  numbers  as  in  the  pre- 
ceding figures. 

Explanation  of  Plate 

Fig.  123.  Three  hours  after  emergence,  showing  the  lighter  areas  between 
the  tracheae ;  124,  after  8  hours — suggestion  of  both  longitudinal  stripes  transverse 
bands;  125,  showing  a  similar  condition  after  10  hours;  126,  similar  conditions  at 
the  end  of  12  to  15  hours;  127,  a  similar  suggestion  of  markings  at  30  hours;  128, 
well  defined  markings  at  36  hours ;  129.  striking  longitudinal  stripes  at  36  hours ; 
130,  heavier  pigmentation  in  the  lines  of  the  trachea  in  the  adult;  131  to  134, 
showing  a  similar  series  for  the  development  of  pigment;  in  C.  tranqucbarica 
Herbst;  131,  6  to  8  hours  after  emergence;  132,  10  hours  after  emergence;  133, 
12  hours  after  emergence;  134,  24  to  36  hours  after  emergence. 


lUJXOlS  BIOLOGICAL  .]JO.\OGRAPIfS 


130 


92  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [486 


PLATE  XI 


Figures  135-146.  Showing  the  ontogeny  of  pigmentation  in  C.  punctulata 
Oliv.,  C.  sexguttata  Fabr.,  Tetracha  Carolina  Linn.,  C.  hirticollis  Say,  and  C.  is 
guttata  Dej. 

Explanation  of  Plate 

Fig.  13s,  C.  punctulata  Oliv.  at  the  end  of  6  hours  after  emergence ;  136, 
after  12  to  13  hours;  137,  after  36  hours;  138,  sexguttata  Fabr.  after  24  hours; 
139,  Tetracha  Carolina  Linn,  at  the  end  of  9  hours  after  emergence ;  140,  the 
adult  elytron;  141-145,  showing  stages  in  the  development  of  pigment  in  hirticol- 
lis Say;  141,  4  hours  after  emergence;  142,  after  6  to  10  hours;  144,  after  12 
hours;  145,  after  16  to  24  hours;  146,  I2  guttata,  after  12  to  18  hours. 


ILLISOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


m.- 


135 


136 


138 


f 

\ — ^ — 

— 2 

r 

\ 

4 
~5— 
~6— 

\ 

142 


COLORS  OF  TIGER  BEETLES 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


PLATE  XII 


Figures  147-187.  Showing  patterns  made  up  cf  longitudinal  and  transverse 
bands  variously  broken  and  contrived.  Follow  the  arrows  in  tracing  out  the  dif- 
ferent directions  of  modification.    For  meaning  of  letters  see  page  9. 

EXPLANATIOX   OF    PlATE 

Figs.  147-149SJ  showing  tHe  typical  transverse  wide  transverse  band  type  of 
pattern  and  modifications;  147,  inahcva  Kunck.  (Madagascar);  148,  andriana  All. 
(Madagascar)  ;   149,  rcgalis  Dej.   (Africa)  ;  149  a  and  b,  the  same. 

Figs.  i50-i67a,  showing  internipta  gahonica  type  of  broken  transverse  bands 
and  their  modification.  The  patterns  of  gabonica  165  and  1650  are  made  up  of 
transverse  bands  and  broken  in  the  lines  of  the  tracheae  with  various  lines  of 
longitudinal  and  transverse  union. 

Figs.  150-152,  showing  the  unusual  patterns  belonging  to  this  group;  150, 
singularis  Chd.  (N.  E.  Africa)  ;  151,  kollari  Gistl.  (S.  Africa)  ;  152,  malaris  Horn 
(S.  A.);  153  and  154,  fiexuosa  Fabr.  (Europe);  155,  striatifrons  Chd.  (India); 
156-1560,  interrupta  Fabr.  (Africa);  157,  montdroi  Bat.  (S.  Africa);  158,  brevi- 
coUis  subsp.  dathrata  Dej.  (Africa)  ;  159-160,  Candida  Dej.  (Africa)  ;  161,  blandi- 
ardi  Fairm.  (S.  Africa)  ;  162,  pddkri  Luc.  (N.  Africa)  ;  163,  vittigcra  Dej. 
(India)  ;  164,  multiguttata  Dej.  (India)  ;  165,  interrupta  Fabr.  subsp.  gabonica 
(Africa);  165a,  interrupta  Fabr.  subsp.  gabonica:  166,  laetescripta  Mtsch.  (E. 
Asia)  ;   167,  lepida  Dej.   (Illinois). 

Figs.  168-1690,  showing  pattern  with  three  longitudinal  stripes;  168.  quccns- 
landica  Sloane  (Australia)  (After  W.  Horn)  ;  169a,  tetragramma  Boisd.  (Aus- 
tralia) ;  170-1700,  muata  subsp.  laticornis  Horn  (Africa);  171,  muata  Horn  (.\f- 
rica)  ;  172,  juno  Horn  (Africa)  ;  173,  1730,  viridis  Raff  (Africa)  ;  174,  giganica 
Raffr.  (Africa)  ;  175,  prodotiformis  Horn  (Africa)  ;  176,  fatidica  Guer.  (Africa)  ; 
177,  miscranda  Horn  (Africa)  ;  178,  gcrstaeckcri  Horn  (Africa)  ;  179.  rcgina 
Kolbe  (Africa)  ;  180-1800,  b,  mechowi  Lued  (Africa)  ;  i8i-i8ia,  braszai  Fit.  (Af- 
rica) ;  182,  ininula  Per.  (Africa)  ;  183,  quadrisiriata  Horn  (Africa)  ;  184-1840, 
peliti  Guer.  (Africa);  174a,  gigantea  Raffr.  (Africa);  185,  junkeri  Kolbe  (Af- 
rica); 186,  vittata  Fabr.  (Africa);  187-1870,  congecnsis  Fit.   (Africa). 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


183  m  184. 

SHELFORD  COLORS  01'  TIGKR  BEETLES 


It?  18/. 

PLATE  XII 


96  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [490 


PLATE  XIII 


Figures  188-240.  Showing  the  domination  of  the  central  stripe  (B),  obliquity 
in  the  middle  band  reversed  from  the  usual  type.  For  meaning  of  letters  see  page  9. 
Follow  the  arrows  in  tracing  out  the  different  lines  of  modification.  Figures  188 
and   iS8a  show  the  reduced  transverse  bands — compare  with   149. 

Explanation  of  Plate 

Fig.  188  and  1880,  C.  flavosiyiiata  Cost.  (Africa)  ;  184.  dk'cs  Gory,  after  Gory 
(India)  ;  190,  aitrovittata  Brll.  (India)  ;  igi,  ccyloneusis  divcrsa  Horn,  after  Horn 
(India)  ;  192,  ccyloneusis  Horn,  after  Horn  (India)  ;  193,  discrcpans  Wak  (In- 
dia) ;  194  and  194a,  hanuandi  Fit.  (India)  ;  195,  196,  intcrruptofasciata  Schm. 
(India);  197,  assamcnsis  Parry  (India);  198-199,  sianicnsis  Fit.  (India);  200, 
andrewesi  vauritti  Horn  (India);  201,  princcps  ducalis  Horn  (India);  202,  auro- 
fasciata  Dej.  (India)  ;  203,  anrofasciata  Dej.  (India)  ;  204-2040,  anrofasciata 
lepida  Gory  (India);  206,  assamcnsis  ?;  207,  crcspignyi  Bat.  (Malay 
Islands)  ;  208,  kachovskyi  Horn  (.Africa)  ;  209,  oskari  Horn  (Africa)  ;  2io-2loa, 
shivah  Parry  (India);  211-212  (After  Schaum),  calligramma  Schm,  (India);  213, 
aurofasciata  Dej.  (India)  ;  214,  hacinorrhoidalis  Wdra.  (India)  ;  215,  burnicisteri 
Fischer  (Asia)  ;  216.  stenodora  Schm.  (Malay  Arch.)  ;  217,  minuta  Oliv.  (India)  ; 
218,  craspedota.  Schm.  (Borneo)  ;  219,  semperi  Horn  (India)  ;  220,  caUigramnm 
Schm.  (India)  :  221,  Prothynia  adonis  rufosignata  Brll.  (Madagascar)  ;  222,  chi- 
ncnsis  japonica  Thnb,  (Japan)  ;  223,  chincnsis  DeG,  (China)  ;  224,  duponti  Dej, 
(India)  ;  225,  e.vima  Vand.  (Malay  Arch.)  ;  226,  fcfriei  Fit.  (Japan)  ;  227,  didyma 
Dej.  (Malay  Arch.);  228,  aurulcnta  Fabr.  (India);  229,  iiotata  Wdm.  (India); 
230,  aurulcnta  Fabr.  (India)  ;  231,  punctata  Fabr,  (India)  ;  232,  Thcratcs  white- 
hcadi  Bates  (Malay  Arch,)  ;  233,  T.  fruhstorferi  ?Iorn  (Tonkin)  ;  234,  T.  spini- 
pennis  Latr.  and  Dej.  (Malay  Arch.)  ;  235,  T.  chaudoiri  Schm,  (Malay  Arch,)  ; 
236,  T.  tiiaindroni  Horn  (Malacca);  237,  T.  crir.ys  Bates  (Malay  Arch.);  238, 
Pcridoxia  hilaris  Fair.  (Madagascar)  ;  239,  Pcridoxia  ftdvipcs  Dej.  (Madagascar)  ; 
240,  Pometon  singnlaris  Fit.   (S,  A.). 


i 


ILUXOIS  BIOLOGICAL  MOXOGRAPHS' 


J'OLUME  3 


234      I  "5  23t,  237^        238  239  2*« 

SHELFORD  COLORS  OF  TIGER  BEETLES  PLATE  XIII 


98  ILLINOIS  BIOLOGICAL  MOXOGRAPHS  [492 


PLATE  XIV 


Figures  241-283.  Showing  patterns  made  up  of  numerous  spots  and  stripes. 
Figures  241  to  243  and  248,  2480,  and  248b  should  be  compared  with  plate  IV, 
figure  38.  In  comparing  the  figures  follow  the  arrows.  For  meaning  of  letters 
see  page  9. 

ExPL.'iN.^TION   OF    Pl.ME 

Figs.  241-241(7^  b,  C.  comprcssii'ornis,  Beh.  (Africa);  242,  kolbci  Horn  (Af- 
rica); 243,  deyrollei  Guer.  (Africa);  244,  maino  Gestro  ( N.  Guinea);  245.  atkin- 
soiii  Gestro  (India)  ;  246,  feisthameli  Guer.  (Africa)  ;  247  (after  Guerin)-247a, 
7iysa  Guer.  (Liberia)  ;  248,  2480,  248&,  lugubris  Dej.  (Africa)  ;  249,  deyrollei  Guer. 
(Africa)  ;  250,  vittata  Fabr.,  after  Guerin  (Africa)  ;  251,  20  guttata  Herbst  (In- 
dia) ;  252,  desgodinsi  Fair.  (Tibet)  ;  253,  latreillei  Guer.  (Kapaur) — the  stippled 
spots  are  dark  and  represent  areas  in  which  spots  usually  occur ;  254-255,  rasti- 
cana  Per.  (S.  Africa);  256,  notata  Boh.  (S.  Africa);  257,  latreillei  Guer.  (Ka- 
paur) ;  258-258(7,  b,  rasticana  Per.  (S.  Africa)  ;  259,  rasticaita  aber  cgregia  Per. 
(S.  Africa)  ;  261,  bioncani  subsp.  licngnici  Per.  (S.  Africa)  ;  262-263,  striolata 
111.  (Burmah)  ;  264,  striolata  subsp.  trisignata  Chd.  (Timor);  265,  neut-.ianni 
Kolbe  (Africa)  ;  266,  pudica  Boh.  (Zulu)  ;  2660,  Boh.  (Transvaal)  ;  267-268, 
escheri  Dej.  (S.  Africa);  269,  nwrginella  Dej.  (Africa);  270,  striolata  111.  (In- 
dia) ;  271,  do  subsp.  trisignata  Chd.  (Timor)  ;  272,  luxcri  Dej.  (Africa)  :  273, 
heros  Fabr.  (Malay  Arch.)  ;  274-274^,  hcros  Fabr.  (Malay  Arch.)  ;  275-2770, 
montciroi  Bat.  (Africa)  ;  278-279,  strachani  Hope  (Africa)  ;  280-2800,  b.  cques- 
tris  Dej.  (Madagascar)  ;  281,  nitidula  Dej.  (Africa)  ;  282,  nilotica  Dej.  (Africa)  ; 
283,  albina  Wdm.   (India). 


//././  A  O/.V  BIOLOGIC  A  L  M  OX  OGRAI'lIS 
fi 


I-Q/A'ME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES  PLATE  XIV 


100  ILLISOIS  BIOLOGICAL  MONOGRAPHS  [494 


PLATE  XV 


Figures  284-328.  Showing  the  patterns  of  North  American  species  belonging 
chiefly  to  the  Mexican  and  C.  argentata  groups  and  having  cross  bands  5  and  6 
both  distinctly  represented  in  the  majority.  For  meaning  of  letters  see  page  9. 
Various  combinations  of  spots  which  go  to  make  up  the  oblique  vitta  of  some  of 
the  species  of  the  group  are  represented  in  figures  291,  296,  297,  311,  312,  313, 
319,  and  320;  compare  these  with  figures  23  and  24  and  78  to  82. 

Explanation  of  Plate 

Fig.  284,  C.  polita  Lee.  (Texas);  285,  abdominalis  Fabr.  (Atlantic  coast, 
U.  S.)  ;  286,  rufiventris  aber.  cumatilis  Lee.  (Texas)  ;  287,  rufiveiitris  Dej.  (East- 
ern U.  S.)  ;  288,  16  punctata  Klg.  (N.  Mex.)  ;  289,  carthagena  subsp.  hentsi  G. 
Horn  (Mass.);  290,  16  punctata  Klg.  (Mexico);  291-2910^  rufiventris  aber.  mcllyi 
Chd.  (Mexico)  ;  292,  trifasciata  Fabr.  (S.  A.)  ;  293-2930,  h,  trifasciata  subsp.  sig- 
nwidca  Lee.  (S.  U.  S.)  ;  294,  carthagena  Dej.  (Mexico)  ;  295,  rufiventris  subsp. 
16  punctatd  Klg.  (Mexico);  296,  rufiventris  aber  mellyi  Chd.  (Mexico);  297, 
niclaleuca  Dej.(S.  A.);  298,  obsoleta  Say  (S.  W.  U.  S.)  ;  299,  fera  Chv.  (Mex- 
ico) ;  300,  pusilla  subsp.  cinctipennis  Lee.  (S.  W.  U.  S.)  ;  301,  punctulata  Oliv. 
(U.  S.  and  Mex.)  ;  302,  argentata  subsp.  aureola  Klg.  (S.  A.)  ;  303-3030,  argentata 
Fabr.  (Brazil)  ;  304,  lunalonga  Schm.  (California)  ;  305,  celeripes  Lee.  (Central 
U.  S.)  ;  306,  cursitans  Lee.  (Miss.  Valley);  307,  schaupii  G.  Horn  (Texas);  308- 
308a,  nephelota  Bat.  (Mexico)  ;  309-3090,  chlorostricta  subsp^  staudingeri  Horn 
(S.  A.)  ;  310,  argentata  subsp.  venustula  Gory  (Mexico)  ;  311-3110,  pusilla  subsp. 
imperfecta  Lee.  (Pacific  States)  ;  312,  luteolineata  Chvr.  (Mexico)  ;  313,  lem- 
niscata  Lee.  (Arizona)  ;  314,  debilis  Bates,  after  Bates  (Mexico)  ;  315,  favergeri 
Brll.,  after  Andouin  and  Brulle  (S.  A.)  ;  316,  3160,  317,  roseiventris  Chvr.  (Mex- 
ico) ;  318,  flavopunctata  Chvr.  (Mexico)  ;  319,  pu^silla  subsp.  imperfecta  Lee.  (Pa- 
cific States)  ;  320,  crarcri  Thms.  (Mexico)  ;  321,  marquardti  Horn — the  only 
Cicindelid  without  a  middle  band  (Sao  Paulo)  ;  322,  hoegei  Bat.  after  Bates 
(Mexico);  323-323(7,  h,  sommeri  Mann.  (Mexico);  324,  anulipes  Horn  (S.  A.); 
32s,  flavopunctata  Chvr.  (U.  S.  and  Mexico)  ;  326,  chrysippe  Bates  (Mexico)  ; 
328,  severa  Laf.   (Gulf  States  and  N.  M.)  ;  328,  striga  Lee.   (Florida). 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


323  323^  3234 

SMELFORD         COLORS  OF  TIGER  BEETLES         PLATE  XV 


102  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [496 


PLATE  XVI 


Figures  329-377.  Showing  the  patterns  of  the  principal  Eurasian  species  ex- 
clusive of  the  flcxuosa  and  longipes-biramosa-liiiiosa  (Oriental)  groups,  with  a 
few  representative  patterns  from  the  genera  Megacephala,  Distypsidera,  Cteno- 
stoma,  and  Collyris.  For  meaning  of  letters  see  page  9.  Figures  330-332  are 
related  American,  species.  Figures  329-355  show  the  typical  and  characteristic 
patterns  of  the  genus  Cicindela  in  which  the  portion  of  the  elytron  nearest  tlie 
scutellum  is  without  spots,  in  which  bands  3  and  3  are  fused  and  5  and  6  are 
separate,  and  the  modifications  of  the  same.  , 

ExPL.\NATio.\  OF  Plate 

Fig.  329,  C.donegalensis  Klg.  (Africa)  ;  330,  hirticolUs  Say  (Illinois)  ;  331,  re- 
panda  Dej.  (Illinois)  ;  332,  is  guttata  Dej.  (Illinois)  ;  33^,,  lunulata  Fabr.  (Europe)  ; 
334,  aphrodisia  Baudi  (Cypris)  ;  335,  lacryiiwsa  Dej.  (Japan)  :  336,  10  guttata 
Fabr.  (Malay  Arch.);  337,  discreta  Schm.  (Malay  Arch.);  338,  nitlda  Wdm. 
(India)  ;  339,  contorta  Fisch.  (Europe)  ;  3^)0,  trisignata  Dej.  (Europe)  ;  341, 
litterifcra  Chd.  (Europe)  ;  342,  alboguttata  Klg.  (Arabia)  ;  343,  suinatrensJs 
Herbst  (India);  344-34S,  orientalis  Dej.  (Europe);  346,  melancholka  Fabr. 
(Europe  and  Africa)  ;  347,  ,?  signata  aber  subsuturalis  Souv.  (Europe)  ;  348. 
circiiindata  Dej.  Europe)  ;  349,  circumdata  Dej.  (Europe)  ;  350,  anguhita  Fabr. 
(India)  ;  351,  sumatrensis  Herbst.  (Oriental  Region)  ;  352,  despecata  Horn,  after 
Horn  (Madagascar)  ;  353,  ancosisconeusis  Harris  (New  York)  ;  354,  funerca  subsp. 
opigrapha  Dej.  (New  Guinea)  ;  355,  variolosa  Blanch.  (Salathy)  ;  356,  galathea 
Thiem.  (Asia)  ;  357,  lyoni  Vig.,  after  Roske  (Europe)  ;  358,  359,  359(7,  germanica 
Linn.  (Europe)  ;  360.  atrata  Pall.  (Europe  and  Asia)  ;  361,  3610,  h,  germanica 
subsp.  ohliquefasciata  Ad.  (Europe)  ;  362,  lactcola  Pall.  (Asia)  ;  363,  gennnata 
subsp.  potanini  Dok.,  after  W.  Horn  (Tibet)  ;  364,  purpurea  subsp.  liiubalis  Klg. 
(Illinois)  ;  365,  campestris,  showing  an  unusual  light  area — the  stippled  portions 
are  dark  areas  with  cuticula  such  as  covers  the  lighter  spots;  366;  ismenia  Gory — 
stippled  areas  as  in  365;  367,  inaura  Linn.  (Europe);  368-369,  fischeri  Adams 
(Europe)  ;  370,  Megacephala  auslralasiae  huineralis  McL.  (N.  W.  Australia)  ; 
,371,  quadrisignata  Dej.  (N.  Africa);  372,  M.  (Styphloderma)  asperata  Wat. 
(Africa)  ;  373,  Distypsidera  flavipes  McL.  (Australia)  ;  374,  D.  gruti  Pasc.  (Aus- 
tralia) ;  375,  Nickerlea  distypsidcroides  Horn,  after  Horn  (Australia)  ;  376, 
Ctenostoiua  inacuUcorne  Chvr.  (Mexico)  ;  377,  Collyris  frushtoferi  Horn  (Ton- 
kin). 


If.I.'XOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


"  3*63  364  365^'       366°^/ 

HtGACEPHAU  DISTVPSIDtRA^^<;^ 


3r,;  368  ^^    3C9 


370       371  ^    372  "       373^^    374        375   ""  376         377 

SHELFORD  COLORS  OF  TIGER  BEETLES  PLATE  XVI 


104  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [498 


PLATE  XVII 


Figures  37S-421.  Showing  the  patterns  of  the  characteristic  groups  of  species 
belonging  to  the  Oriental  and  Australian  Regions.  For  meaning  of  letters  see 
page  9.  They  are  in  general  of  a  character  such  as  is  commonly  designated 
as  specialized  but  show  some  viniisual  combinations  of  areas  which  tend  to  con- 
firm tlie  general  interpretation  here  presented. 

ExPL.^N.\TiON  OF  Plate 

Figs.  .vS-37?a,  b,  C.  araih^if'cs  Schm.  (Borneo);  379-j79a,  copnlatci  Schm. 
(India);  380,  aiichoralis  subsp.  iJUiutatissiiiia  Schm.  (China);  381-382,  ornata  Fit. 
(India);  383,  384,  385,  psammodroina  Chvr.  (China);  386,  387,  388,  anchoralis 
subsp.  punctatissima  Schm.  (China)  ;  385,  anchoralis  Chvr.  (China)  ;  390-391, 
q'.iadrilineata  subsp.  renei  Horn  (India);  392-393,  ypsilon  Dej.  (Australia);  394, 
rafflesia  Chd.  (Australia)  ;  395-3950,  albicans  Chd.  (Australia)  ;  396,  longipes 
Fabr.  (Malay  Islands)  ;  397-397a,  4  lincata  Fabr.  (India)  ;  398,  398(7,  4  lincata 
subsp.  renei  Horn  (India)  ;  399,  singularis  Chd.  (Nubia)  ;  400,  longipes  Fabr. 
(Malay  Islands)  ;  401-4010,  wapleri  Lee.  (Louisiana)  ;  402-402U,  mucronata  Jord. 
(Malay  Islands);  403,  pupilligcra  Schm.  (New  Guinea);  404,  limbaia  Schm.  (In- 
dia) ;  405,  ivaindroni  Horn  (India)  ;  406,  biratiiosa  Fabr.  (India)  ;  407,  bellana 
Horn  (India);  4o8,funerata  subsp.  barbata  Horn  (New  Guinea);  409,  tuberculata 
Falir.  (.Australia);  410,  tuberculata  aber  latccincta  White  (New  Zealand);  411, 
harryi  Whitei  (New  Zealand)  ;  412-413,  lO  guttata  Fabr.  (New  Guinea)  ;  414, 
niastcrsi  ?klcL.  (Australia)  ;  415,  fcrcdayi  Bates  (New  Zealand)  ;  418,  tuberculata 
Fabr.  (New  Zealand);  419,  dunedcnsis  aber  zcal;cficldi  Bates  (New  Zealand); 
420,  fcrcdayi  Bates   (New  Zealand)  ;  421,  pcrhispida   Brn.   (New  Zealand). 


ILLISOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


SMELFORD 


7  ^-^        ""  419  4?0     --^      ■1^1 

COLORS  OF  TIGER  BEETLES  PLATE  XVII 


106  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [500 


PLATE  XVIII 


Figures  422-455.  Showing  the  higlily  specialized  patterns  of  the  South  Amer- 
ican species  belonging  chieflj'  to  the  cnfrasccns  and  argciitata  groups  of  species. 
For  meaning  of  letters  see  page  9.  All  the  types  have  representatives  in  which 
pigment  has  almost  entirely  disappeared  as  a  rule  and  there  is  a  strong  tendency 
for  the  area  of  the  media  trachea  to  degenerate  along  with  the  reduction  of  that 
treachea   (see  figures  16  and  20). 

EXPLAN.'^TION   OF    PlATE 

Figs.  422-4220,  h,  C.  apiata  Dej.  (S.  A.)  ;  423,  apiata  aber  clausseni  Putz. 
(S.  A.)  ;  424,  gormazi  Reed.  (Chili)  ;  425,  mixta  Horn  (Ecuador)  ;  426,  trifas- 
ciata  Fabr.  (S.  A.)  ;  427-4270,  b,  graphiptera  Dej.  (S.  A.)  ;  428-4280,  after  Chev- 
rolot  4286,  patagonica  subsp.  cherubim  Chvr.  (S.  A.)  ;  430-4300,  b,  marginata  Fabr. 
(Texas)  ;  431-4310,  b,  nivea  Kirby  (S.  A.)  ;  430-4320,  gabbi  G.  Horn  (California)  ; 
433,  trisignata  Dej.  (Asia)  ;  434,  unidentified  species  from  Arica,  Peru,  in  the 
Oxford  University  Museum ;  435,  curvata  Chvr.  (Mexico)  ;  436,  dorsalis  aber 
saulcyi  Guer.  (Texas)  ;  437-4370,  b,  c,  dorsalis  Say  (Mass.)  ;  438,  malaris  Horn 
(Pebas,  Amazons)  ;  439-4390,  ncvadica  var.  knausi  Leng  (Kansas')  ;  440,  ciipras- 
cciis  Lee.  (Illinois)  ;  441  hamata  Brll.  (Mexico)  ;  442,  chloroccphala  Chv.  (Vera 
Cruz,  Mex.)  ;  443,  leucohoe  Bat.  (Mexico)  ;  444,  macroncma  Chd.  (Mexico)  ; 
445.  togata  Laf.  (Texas)  ;  446,  atiraria  Klg.  (S.  A.)  ;  447,  boops  (West  Indies)  ; 
448,  macronema  Chd.  (Mexico)  ;  449,  pamphila  Lee.  (Texas)  ;  450,  togata  Lee. 
(Texas)  ;  451,  californica  praetexta  Lee.  (Texas)  ;  452,  marginata  Fabr.  (Texas)  ; 
453n,  ''.  c,  d,  'cvapleri  Lee.   (Louisiana). 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


OLUME  3 


449^^         •fbo  451  452  4<3j         453/,  «b3<:  45Jj  454/  454r 

SHHLF0RI3  COLORS  OF  TIGER  BEETLES  PLATE  XVIII 


108  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [502 


PLATE  XIX 


Explanation  of  Plate 

Figure  455.  Showing  the  equipment  used  in  the  experiments  on  modification 
of  tiger  beetle  color  and  color  patterns. 

The  experiments  were  conducted  in  four  chambers ;  two,  A  and  B,  which 
were  of  galvanized  iron,  rested  with  their  bottoms  in  a  concrete  tank  of  running 
water.  Trey  were  wrapped  with  cheese  cloth  and  sprayed  with  jets  of  water  on 
two  sides  which  kept  the  mean  temperature  at  21°  C.  throughout  the  summer. 
The  other  two,  C  and  D,  were  heated  from  above  with  electric  lights,  blackened 
in  C  and  separated  from  the  main  chamber  by  a  copper  jacket  in  D.  These  were 
were  heated  to  a  point  10°  C.  above  the  temperature  of  the  greenhouse  except 
during  the  middle  of  the  day.  The  switch  shut  off  the  heat  at  about  35°  C.  air 
temperature  and  the  sun  continued  to  heat  the  chamber  so  that  the  maximum 
soil  temperature  sometimes  reached  40°  C.  or  more  by  midafternoon.  Air  was 
drawn  through  the  tanks  by  filter  pumps  and,  in  the  case  of  the  control  tanks, 
through  sulfuric  acid  for  the  dry  one  and  water  for  the  moist  one,  but  this 
intake  was  not  maintained  for  the  high  temperature  tanks  at  all  times  because 
of  mechanical  difficulties.  The  moisture  in  the  moist  chambers  was  maintained 
by  frequent  additions  of  water  to  the  soil,  while  in  the  dry  chambers  as  little 
water  as  possible  was  added.  H ,  sulphuric  acid  bottles ;  S,  mercury  switch ;  T, 
thermostat ;  B,  batteries ;   W,  water  bottles ;  SP,  spray  nozzles ;  C,  cloth  cover. 


ILLISOIS  BIOLOGICAL  MOSOCRAPHS 


rOLCME  3 


SHKLFORD 


COLORS  OF  TIGER  BEETLES 


no  ILLIXOIS  BIOLOGICAL  MOXOCRAPHS  [504 

PLATE  XX 


Figures  456-465.  Showing  the  color  patterns  of  specimens  of  C.  tranqiic- 
barica  Herbst.,  C.  piirpurca  liiiibalis  Klg.,  and  C.  sci:lcllaris  lecontci  Hald.  sub- 
jected to  high  temperature  under  moist  and  dry  conditions  and  placed  in  an  ice 
box  during  their  prepupal  and  pupal  life.  With  them  are  shown  controls  which 
were  kept  at  normal  temperatures  or  lower  and  designated  with  letters  a  ,  b' ,  etc., 
and  a  few  collected  from  the  normal  habitat  from  the  same  generation,  desig- 
nated :c''. 

ExPL.\N.\TION   OF    Pl.ATE 

Fig.  456(J-(7,  the  elytra  of  seven  specimens  of  C.  tranquebarica  which  passed 
the  late  larval,  prepupal,  and  pupal  stages  in  a  warm  moist  chamber ;  mean  tem- 
perature of  the  soil,  37°  C. ;  maximum  for  the  warmest  week,  40°  C. ;  control, 
456a',  b' ,  'ii/,  at  21°  (Experiment  56)  ;  457a-b,  the  elytra  of  two  specimens  of 
C.  tranquebarica.  which  passed  the  late  larval,  prepupal,  and  pupal  stages  in  a 
warm  dry  chamber,  mean  temperature  40°  C. ;  control,  4S7a'-e''W  at  21  °  C. 
(Experiment  57)  ;  458,  the  same  as  457  but  dry  instead  of  moist;  4S&a'-b'  control 
of  the  same  (Experiment  58^:  461.  the  same  moist  warm  treatment  as  described 
under  456  applied  to  C.  purpurea  .liiiibalis;  462,  the  same  as  461  but  dry  in- 
stead of  moist;  for  normal  patterns  see  figure  512,  plate  XXVIII;  a  collected 
specimen  from  the  same  generation  showing  the  e.xtreme  type  of  cross  band  re- 
duction and  forward  curvature  found  either  in  the  controls  or  the  collections 
from  the  habitata ;  459,  showing  the  pattern  of  a  specimen  of  C.  tranquebariia 
which  was  forced  through  its  transformations  in  the  fall  by  a  temperature  of 
Z7°  C.  beginning  October  I,  so  that  there  was  no  hibernation.  This  specimen 
was  one  emerged  early  in  December.  The  others  emerged  in  June  but  none  of 
them  showed  any  modification ;  46oa-&,  the  same  treatment  as  456  but  dry  instead 
of  moist  (Experiment  60)  ;  463,  showing  the  patterns  of  specimens  of  C.  scutcl- 
laris  lecontei  Hald.  subjected  to  conditions  similar  to  those  mentioned  for  figure 
456;  463^  shows  markings  reduced  below  anything  ever  collected  near  Chicago 
or  produced  in  the  controls  (Experiment  63)  ;  464<;,  b,  c,  showing  the  patterns 
of  elytra  of  C.  scutellaris  lecontci  subjected  to  mean  temperature  of  39°  C.  under 
very  moist  conditions  (Experiment  64)  ;  4651;.  b,  c,  showing  the  elytral  patterns 
of  two  specimens  of  C.  scutellaris  lecontci  Hald,  kept  in  an  ice  box  during  the 
pupal  and  prepupal  stages;  10  to  12°  C.  from  July  29  to  September  3;  16  to  20° 
September  3  to  October  16;  466  shows  the  elytron  of  a  specimen  kept  at  a  mean 
temperature  of  40°  C,  moist;  466a',  b',  c  are  the  control  of  the  same  kept  at 
21°  C. ;  Ad'w' ,  x',  y',  z  show  elytra  of  specimens  collected  in  the  habitat  from 
which  the  experimental  material  came,  selected  to  show  the  range  of  variation ; 
468a  and  w'  .  .  a  shows  the  middle  band  of  a  specimen  of  C.  hirticollis  showing 
the  rounded  angle,  transverse  portion  perpendicular  to  the  inner  border  of  the 
elytron  and  the  hooked  portion  at  the  eiid  rounded — compare  with  the  normal 
shown  in  46&C1'. 


ILLINOIS  lilOLOGIC.lL  MONOGRAPHS 


VOLUME  3 


4flf)    EXPtKIMlMSb 


e 


rt^N^      ^'  / 


,/\«l      ^^ 


^0^^   <5  \^  uT-^    a'^^S    d^^    c^^   d' 

^56    CONTROL 5fi       -,  ''57 


EXP58    458C(WTB0l    58        ""*  ^9       ''^^  EXPERIMENT 60  '^'''tXPei    ''^^EXpl^     CONTROLS 


EXPERIMtNTf,3 


/;^-V7      c^^-Tl     "^^     ^ 

'lllb  tXPtRIMENT  h.S 


,f?5  -5^  ^^.bJR^  ^^ ^^  y^ ^^ 

*"''     rnNTimi  fiS        _.  '"'"cyoCfi         467      rnurimi  ci   ■  .^  ^~^ 


C0NTR0166      ->  ''^'TXP66        ''6'     CONTROL67- 


SI 

s^txpea 


SHELFORD  COLORS  OF  TIGER  liEETLES  PLATE  XX 


112 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[506 


PLATE  XXI 


Explanation  of  Plate 

Figure  469.  Showing  the  range  of  variation  in  the  group  of  races  included 
under  the  name  tranguebarica  Herbst.  The  classes  of  patterns  are  arranged  in 
a  series  a,  b,  c,  d,  e,  f,  etc.,  from  left  to  right  and  the  percentage  of  individuals 
in  each  class  for  several  localities  is  graphically  represented.  At  the  top  is  indi- 
cated the  color  of  the  elytra  to  which  the  patterns  belong  but  these  do  not  fall 
in  the  same  classes  as  the  patterns.  The  graphs  arc  numbered  and  the  localities 
which  they  represent  are  numbered  on  figure  4690. 

The  graphs  are  for  the  following  localities,  approximate,  altitude,  etc. 

Vegetation 
Altitude 
2020  ft. 
4S00  ft. 
1060  ft. 
2600  ft. 
100+ ft. 
2500  ft. 
1500  ft. 
200  ft. 
1180  ft. 
7536  ft. 


No.  Locality 

1.  Las  Vegas,  Nev. 

2.  Provo,  Utah 
o.  San  Bernardino,  Cal. 
.(.  Hagerman,   Idaho 

5.  Galveston,  Tex.   (vicinity) 

6.  Dodge  City,   Kan. 

7.  Fayetteville,  Ark. 

8.  Framingham,  Mass. 
g.  Aweme,  Manitoba 

10.  Alamosa,  Colorado 

The  classes  into  which  they  are  divided  ar 

tlie  curves  are  divided. 


No.  Specimens 

and  Climate 

8 

Desert 

IS 

" 

10 

Semi  desert 

5 

" 

130 

Savanna 

69 

Steppe 

4-^ 

Deciduous  forest 

1-49 

"             " 

73 

Steppe 

7 
somewhat 

arti 

icial  and  some  of 

ILLISOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


O         O  o        o  o 


o        S       "=> 


SlIELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  XXI 


114  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [508 


PLATE  XXII 


Explanation  of  Plate 


Figure  4691!.  Showing  the  tlistrilnitioii  of  C.  tranquebarica  in  N.  America. 
The  numbers  refer  to  the  graphs  sliown  in  I'igure  469.  The  legend  shows  the 
elvtral  color. 


ILUXOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


SHHLFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  XXII 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[510 


PLATE  XXIII 


Explanation  of  Plate 


Figure  470.  Showing  the  range  of  variation  in  the  group  of  races  included 
under  C.  scuiellaris  Say.  General  plan  as  in  figure  469,  plate  XXI.  Here  the 
individuals  are  arranged  into  classes  which  are  strictly  geographic ;  beginning  in 
Massachusetts  at  the  extreme  left,  they  are  arranged  as  encountered  as  one  passes 
southward  along  the  Atlantic  coast  and  westward  through  the  Gulf  States.  From 
Dallas,  Texas,  classes  are  arranged  in  order  as  one  passes  northward  through 
western  Oklahoma,  Kansas,  Nebraska,  and  South  Dakota  and  tlien  eastward 
through  the  Great  Lakes.  The  classes  on  the  extreme  right  (s  and  0  are  from 
Aweme,  Manitoba. 


No. 

Climate 

Locality 

Specimens 

Generation 

Collector 

Altitude 

or  Vegetation 

I. 

Framingham,  Mass 

51 

1902 

1904 

A.  C.  Frost 

220  ft. 

Deciduous  Forest 

2. 

Providence,  R.  L 

8S 

1902 

P.crt  Nock 

soft. 

" 

3- 

Aqueduct,  N.  Y. 

98 

1903 

L.  H.  Joutel 

50  ft. 

"              " 

4. 

Raleigh,  N.  C. 

59 

1904 

C.  S.  Eriniley 

320  ft. 

"              ** 

s. 

Mobile,  Ala. 

20 

191 1 

V.  E.  Shelford 

50  ft. 

It              tt 

6. 

Medora,  Kan. 

150 

1904 

" 

1600  ft. 

Steppe 

7- 

Topeka,  Kan. 

150 

1904 

" 

900  ft. 

Savanna 

a. 

Elma,  Iowa 

30 

1902 

-1904 

Rev.  J.  C.  Warren 

1000  ft. 

" 

9- 

Starved  Rock 

(Utica),  111. 

40 

1905 

-1906 

V.  E.  Shelford 

470  ft. 

" 

0, 

Miller,  Ind. 

200 

1904 

-1905 

" 

600  ft. 

Deciduous  Forest 

t. 

Aweme,  Man. 

' 

N.  Griddle 

1 1 80  ft. 

Steppe 

n.f.rXOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


05  OO 

SllELFOKU 


COLORS  OF  TIGFR  CEETLFS 


PMTE  XXI 1 1 


118  ILLIXOIS  BIOLOGICAL  MONOGRAPHS  [512 


PLATE  XXIV 


Explanation  ok  Plate 

Figure  470a.  Showing  tlie  distribution  of  the  group  of  races  included  under 
C.  sciitcUaris  Say.  The  legend  indicates  the  color  of  tlie  elytron.  The  nunibers 
(italics)  refer  to  the  classes  of  color  patterns  indicated  in  figure  470,  plate  XXIII. 
The  lines  and  numbers  indicate  mean  annual  rainfall  in  inches.  The  mean  annual 
rainfall  to  the  left  or  west  of  the  line  designated  as  20  is  less  than  20  inthes,  to 
the  right  or  east  more  than  20  inches.  To  the  east  and  south  of  the  line  desig- 
nated as  30  the  mean  annual  rainfall  is  more  than  30  inches.  To  the  east  and 
south  of  the  line  designated  as  40  it  is  more  than  40  inches.  Note  that  the  colors 
are  fairly  well  correlated  with  rainfall. 


ILLIXOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  XXIV 


120 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[514 


PLATE  XXV 


Explanation  of  Plate 

Figure^  471.  Showing  the  range  of  variation  in  the  group  of  races  falling 
under  C.  purpurea  Oliv.  General  plan  of  arrangement  as  in  the  preceding  charts 
on  other  species  (Pis.  XXI  and  XXIII).  In  the  case  of  this  species  the  immacu- 
lated  elytroned  types  which  are  very  rare  in  occurrence  are  taken  as  a  central 
type.  Those  to  left  are  level  ground  inhabitants  in  which  the  reduction  of  pat- 
terns is  characterized  by  a  withdrawal  of  the  middle  band  from  the  elytral  mar- 
gin. Those  to  the  right  are  the  steep  clay  bank  inhabitants,  except  possibly  class 
"t"  (C.  decemnotata  Say);  classes  a,  b,  c.  C.  ciinarrona  Lee;  d-h,  C.  purpurea 
Oliv.,  graminea  Schpp.,  audobonii  Lee,  spreia  Lee.  Those  to  the  right  are  splen- 
dida,  Hentz,  transversa  Leng,  denvcrensis  Cas.,  limbalis  Klg.  The  graphs  are  for 
the  following  localities  with  approximate  altitudes,  vegetation,  etc. 

Climate 


Locality 

No.   Specimens 

1      Color  or  Race 

Altitude 

or  Vegetation 

I. 

Fort  Collins, 

Colo. 

7 

Green  and  black 

5600  ft. 

Steppe 

2. 

Framingham, 

Mass. 

128 

Winecolor,  brown, 
some  greenish 

100  ft. 

Deciduous  Forest 

3- 

Puget  Sound, 

Wash. 

7 

Green 

10  ft. 

Conifer 

4- 

Kimmich,  Mo 

29 

trans'i'crsa 

42s  ft. 

Deciduous  Forest 

S- 

Topeka,  Kan. 

100 

splendida 

900  ft. 

Savanna 

6. 

Glencoe,  111. 

54 

limbalis 

6coft. 

" 

7- 

Aweme,  Man. 

10 

lo.-^o  ft. 

Steppe 

8. 

Sedalia,  Colo. 

Red  Classes,  p-s 

5800  ft. 

" 

ILLINOIS  BIOLOGICAL  MOXOGRAPHS 


VOLUME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  XXV 


122  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [516 


PLATE  XXVI 


Explanation  of  Plate 


FiGUKE  471a.  Showing  the  distribution  of  the  limbalis,  denverensis,  transversa, 
and  10  notata  races  of  C.  purpurea  with  numbers  referring  to  the  graphs  in  figure 
471,  plate  XXV,  and  legend  showing  colors. 


ILLIXOIS  BIOLOGICAL  MOyOGRAPHS 


J-QLUME  3 


SHELFORD 


COLORS  OF  TIGER  BEETLES 


PLATE  XXVl 


124  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [518 


PLATE  XXVII 


Explanation  of  Plate 


Figure  472.  Showing  the  distribution  of  the  purpurea,  graminea,  audobonii, 
and  cimarrona  races  of  C.  purpurea  with  numbers  referring  to  the  graphs  on 
figure  471,  plate  XXV,  and  legend  showing  colors. 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  3 


Q  tfiye  -  BROWN    pnrporea  Oliv. 

aQuuTona  Lee. 
^BLACK    Atidubomi  Lee. 
□  RED 
X  Cfl££,v  (na=;cai  Schpp. 


SHELFORD 


COLORS  OF  TIGER  BEETLES  PLATE  XXVII 


126  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [520 


PLATE  XXVIII 


Showing  the  parallelism  of  patterns  of  the  north  stem  of  W.  Horn's  phylogenj', 
and  C.  sexguttata  Fabr.     Compare  the  rows  with  one  another. 

Explanation  of  Plate 

■Figs.  473-474,  tranquebarica  Herbst  subsp.  plutonica  Cas.  (California)  drawn 
from  descriptions  by  Leng :  475-478,  do.  subsp.  vibcx  Horn  (Las  Vegas,  Nev.)  ; 
479,  do.  (San  Bernardino,  Cal.)  ;  480,  greenish  brown  form  of  tranquebarica  (Ha- 
german,  Idaho)  (roguensis  Harris)  ;  481,  tenuicincta  Sch.  (Salt  Lake)  ;  482, 
tranquebarica  (Framingham,  Mass)  ;  483,  tenuicincta  Schpp.  (Saltair,  Utah)  ;  484, 
tranquebarica  Herbst  (Alamosa,  Colo.)  ;  485,  do.  (Las  Vegas,  Nev.)  ;  486-490, 
scutellaris  Say,  varieties — see  figure  468  and  description ;,  491,  echo  Cas.  (Great 
Salt  Lake)  ;  492,  willistoni  Lee.  (Lake  Como,  Wyo.)  ;  492,  fulgida  Say  (Kansas)  ; 
494-496,  latesignata  Lee.  (San  Diego,  Cal.);  497-501,  pulchra  Say  (499-501 — .Al- 
pine, Texas,  drawing  supplied  by  Prof.  H.  F.  Wickham,  from  specimens  in  his 
collection)  ;  502,  latesignata  aber.  tenuicincta  Blaisdell  (Saltair,  Utah)  ;  503-505, 
longilabris  Say,  varieties ;  504-505,  (N.  Mexico)  ;  506-518,  purpurea  Oliv.,  varie- 
ties (see  Fig.  470)  ;  508-509,  516-518  (Sedalia,  Colo.);  519,  generosa  subsp.  man- 
toba  Leng.;  522-523,  sexguttata  (Onaga,  Kansas);  524,  do.  (Chicago);  525-526, 
do.  (Woods  Holl.)  ;  527,  sexguttata  subsp.  patruela  Dej.  (Lakehurst,  N.  J.)  :  528, 
/.?  guttata  Dej.  (Chicago);  529,  ancosisconensis  Harris;  530,  repanda  Dej.  (Chi- 
cago); 531-532,  generosa  Dej.;  531,  do.  (Framingham,  Mass.);  532,  do.  (Lake- 
hurst, N.  J.)  ;  533-534,  venusta  Lee.  (Aweme,  Man.)  ;  535-536,  limbata  Say 
(Aweme,  Man.)  ;  536,  purpurea,  showing  reduced  and  shortened  marking. 


ILLIXOIS  BIOLOGICAL  MOXOGRAPLIS 


VOLUME  3 


.ijl^ 


/r'^ 


SMELFORD  COLORS  OF  TIGER  BEETLES  PLATE  XXVIII 


128 


ILLIXOIS  BIOLOGICAL  MONOGRAPHS 


[522 


PLATE  XXIX 


Showing    Development    and    General    Modification    of    Colors    in    Experiments    in 
C.  scutellaris  lecontei  Hald. 


Figs.  ; 

538, 
539' 
540. 
541 
542. 

Figs.  543- 
543 
544 
545 
546 
547 
548. 
549 
550. 
551. 
55-. 
553 
554. 
555. 


556. 


558. 


EXPLAN.\TI0N   OF    PlATE 

542.  Development  of  color  in  the  ventral  side. 

4  hours  after  emergence. 

10  hours  after  emergence. 

11  hours  after  emergence. 

15  hours  after  emergence — adult  coloration. 

Adult  coloration  in  a  dark  individual. 
549.     Color  development  and  color  changes  in  an  individual  of  C  lecontei. 
I  hour  after  emergence. 

1 1  hours  after  emergence. 

13  hours  after  emergence;  compare  with  553. 

15  hours  after  emergence. 

3  to  IS  days  after  emergence ;  drawn  at  end  of  third  day. 

42  days  after  emergence. 

85  days  after  emergence. 

C.  lecontei,  color  of  modal  class,  Miller,  Ind.,  April,  1906. 

C.  lecontei.  Miller,  Ind.,  June,  1906. 

C.  lecontei,  color  of  modal  class.  Miller,  Ind.,  .^pril,  1905. 

C.  scutellaris  rugifrons,  typical  specimen,  Raleigh,  N.  C. 

C.  scutellaris,  typical  specimen,  Topeka,  Kansas   (not  modal  class). 

C.  lecontei,  larvae  subjected  to  hot  dry  conditions  during  prepupal 
and  pupal  stages,  note  reduced  markings  and  color — compare  with 
normal  ontogeny  series  above  (Experiment  63)  ;  mean  tempera- 
ture 37°;  dry;  compare  with  554  and  553. 

C.  lecontei,  larvae  forced  by  high  temperature  and  brought  through 
without  hibernation  (Experiment  591! ;  mean  temperature  37°  C. ; 
moist. 

C.  lecontei  modified  by  cold  conditions  during  the  pupal  stage;  (E.xperi- 
ment  65)  ;  mean  temperature.  12°  C. ;  moist.  Note  dull  color  and 
peculiarities  of   markings. 

Peculiar  individual  from  Starved  Rock  (Utica),  111.,  showing  the  ten- 
dency for  all  the  highly  colored  species  to  produce  purple  forms 
occasionally.     This  type  occurs  at  Utica  on  the  coarse  sands. 


PLATE  XXTX 


542 


^  rt 


r 


544 


543 


545  546  547  548 


550  551 


552 


555  556 


557  558 


523]  COLORS  OF  TIGER  BEETLES— SHELFORD  129 


PLATE  XXX 


130  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [524 


Sliowing   Color   Development   and   General   Modification   in   Experiments   on 
Species  Named. 

Explanation  of  Plate 

Figs.  559-562.    Color  development  in  Cicindela  hirticollis. 

559.  Condition    4  hours  after  emergence. 

560.  Condition  15  hours  after  emergence. 

561.  Condition  21  hours  after  emergence. 

562.  Condition  21  days  after  emergence,   full  adult  color. 
Figs.  563-565.     Color  development  in  C.  purpurea. 

563.  Condition  20  hours  after  emergence. 

564.  Condition    4  days  after  emergence. 

565.  The  same  specimen  as  in  figure  6,  killed  and  dried  on  the  fourth  day 

after  emergence. 
Figs.   565-570.     Experimental   modification    of   color   and   color   pattern    by   condi- 
tions during  the  prepupal  and  pupa!  stages. 

566.  Dwarfed    specimen   of    C.   hirticollis  produced   by    forcing   the   larvae 

without  hibernation  in   their  last  vifinter    (Experiment  70)  ;   mean 
temperature,  37°   C. ;  moist. 

567.  Normal  individual  of  C.  tranquebarica,  collected  in  the  field. 

568.  Specimen  with  color  modified  by  being  kept  in  an  ice  box,  during  the 

pupal  stage,  like  variety  in  eastern  mountains    (Experiment  6Sa)  ; 
mean  temperature,   12°   C. ;   moist. 

569.  Specimen  with  both  pattern  and  color  modified  by  hot  dry  conditions 

(Experiment  60);  mean  temperature,  37°   C. ;  dry.     Like  variety 
in  the  western  states. 

570.  Specimen  with  both  pattern  and  color  modified  by  hot  wet  conditions, 

like  variety  in  the  moist  southern  states  (Experiment  56)  ;  37°  C. ; 
moist. 


PLATE  XXX 


559 


562 


566 


525]  COLORS  OF  TIGER  BEETLES—SHELFORD  131 


PLATE  XXXI 


132 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[526 


Showing    Color    Development    and    General    Moditication    in    Experiments    on 
C.  purpurea  subsp.  limbalis. 

Explanation  of  Plate 


Figs.  571-574.     Color  development  in  C.  purpurea  subsp.  limbalis. 
571.     Condition  at  emergence. 

Condition  12  hours  after  emergence. 

Condition  34  hours  after  emergence. 

Condition  15  days  after  emergence. 

Normal  collected  individual. 

Specimen  killed  and  dried  vthexi  at  stage  shown  in  figure  573. 

Experimentally  modified  individual,  in  hot  dry  conditions  during  pre- 
pupal  and  pupal  stages.  Resembles  specimens  from  eastern  Kan- 
sas. 

Specimen  with  color  modified  by  being  kept  in  an  ice  box  during  the 
pupal  stage   (Experiment  656);  mean  temperature,  12°  C. ;  moist. 

Specimen  modified  by  hot  moist  conditions  during  the  prepupal  and 
pupal  stage   (Experiment  61);  mean  temperature,  37°  C. ;  moist. 


572 
573 

574- 
575 
576. 

577. 


579- 


f^ 


PLATE  XXXI 


57 


572 


573 


574 


575 


576 


I 


\J'^ 


578 


579 


527]  COLORS  OF  TIGER  BEETLES— SHELFORD  133 


PLATE  XXXII 


134  ILLIXOIS  BIOLOGICAL  MOXOCRAPHS  [528 


Explanation  of  Plate 

Figure  580.  Showing  the  geographic  distribution  of  types  and  patterns.  The 
first  series  at  the  left  are  world-wide  in  distribution,  being  most  generalized  in 
Eurasia  and  North  America.  The  second  group  of  patterns  belong  to  several 
groups  of  species  but  all  are  characterized  by  the  presence  of  three  spots  at  the 
base  and  along  the  elytral  suture.  They  are  most  numerous  in  Africa  and  India. 
The  next  group  shows  the  relatively  rare  type  with  the  pattern  oblique  but  in  the 
opposite  direction  from  the  slope  of  the  tip  of  the  elytron.  The  last  type  is  one 
showing  peculiar  joinings  of  markings  characteristic  of  species  found  chiefly  in 
Indo-Australian  region. 


luj.voi':  r.ioiociCAi.  MoxncK.irir 


\-oi.VMr.  3 


^rzp 


SlIKLFORl)  COLORS  OF  TIGER  RRF.TI.F.S  PLATF  XXXII 


The  I'opics  of  this  vohiiiie  \vci-i>  distrihuted  as  follows: 

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ILLINOIS  BIOLOGICAL 
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m 


